Biggest PC Building Mistakes From The Community


Although we are a community of PC builders, some of us novices, some of us experts, there is unlikely any among us who can honestly say they haven't made a mistake in a build. Some of us have been fairly lucky, and the worst mistake we ever made was to buy an incompatible component for a build, while others have seen their systems literally go up in flames.

To share in the amusement of our own mistakes and those of our community, we asked readers and forum members to submit their biggest PC building blunders, and we have picked out the best of these to list here. We hope you enjoy reading and discussing these stories while remaining polite and respectful. After all, sometimes mistakes are the best learning experiences, whether those mistakes happen to us, or to others.

I'll kick things off with my biggest PC building mistake. It was only about three years ago, and I decided to give Crossfire a try with two AMD Radeon HD 7850 graphics cards. I inserted the two cards in my motherboard, connected them with the Crossfire cable, started up a game and noticed that one of the GPUs had almost immediately hit 100 degrees!

Turns out the motherboard I used had the PCI-E slots slightly too close together, and the cooler mounting screws on the second GPU had blocked the fan on the primary GPU from spinning. Not only that, but from the force of trying to spin, one of the fan blades cracked clean off. You can imagine how dumb I felt.

If you've finished laughing at my blunder, let’s look at some of yours. The stories are organized into hardware categories with five stories in each section. We've also left the story submissions as they were submitted, which is to say, unedited.

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CPU Mistakes

First up are CPU mistakes. A small note before we get started. In our deliberation we decided to rule out any entries that involved bending CPU pins by mistake, simply because it was just too common.

Our first submission, which is probably the biggest mistake from the Tom’s Hardware community manager, Joe Pishgar, involves him taking a Dremel to a CPU.

Back when I was in middle school, I sawed an AMD K6-2 CPU in half using a Dremel. See, it was a different pin configuration than the socket for the motherboard I was using, and I wanted it to fit. Yes, there was some peer pressure involved. I think the biggest stupidity was plugging the thing in and pressing the power button. The smell was quite impressive. Since then, I've always associated the scent of computer components burning with a deep sensation of personal guilt. Life lesson: Never take a Dremel to a CPU.”

Joe later reported back to tell us that this was not even his own CPU. That’s gotta hurt to walk in and find half your CPU sitting on the counter and the other half smoking up the room.

The next submission comes from user “weberdarren97,” who went through a series of CPUs and motherboards while pushing for higher clock speeds.

“I tried to get the Asus m5a78l-m/usb3 to power the AMD FX 8350 at 5GHz. Yeah, I burnt out the power delivery systems on the motherboard and bricked the CPU. So I got another 8350 and then got the Asus M5A99FX PRO R2.0 motherboard and attempted to make it to the magical 5.2GHz, then I couldn't figure out why my CPU burnt up after like fifteen seconds... I forgot to put on thermal paste.

So then I got my third 8350 and put it in correctly then I actually managed to get to 7.15GHz just out of luck, I seem to have won the silicon lottery with this last CPU.”

The third submission is from user “Kurz,” and it comes as a healthy reminder to never work on a PC while it is turned on.

Mine isn't as glamorous. I was lazy and didn't want to turn off the computer to move components around in the case. I think I had a x800 XL AMD card. The screw driver touched the back of the card, Sparks flew and the computer froze up. The computer booted back up just fine. Though gaming performance was impacted...

I am not proud of this but I was an teen at the time. I successfully RMA'd the card and get it replaced.”

Next up is a submission from user “urishima,” who made the mistake of leaving the protective plastic coating on his CPU cooler when installing it. I’d say this one came off lucky, because if "urishma" hadn’t noticed it soon enough or applied too much pressure while mounting the cooler, then this could have turned out much worse.

Forgot to remove the little bit of transparent plastic that covered the base plate of the after-market cooler for my Phenom II. I only realized why the temps of my CPU would skyrocket as soon as I turned it on, when I removed the cooler to reapply thermal paste.

There was no lasting damage, but I felt like right idiot at the time.”

Next up is “thedigitaldevil,” who made the mistake of using the wrong thermal paste, which essentially welded his CPU to the CPU cooler.

This took place when I was about 22 I think which would be roughly 13 years ago. I can't remember the CPU socket type of model but it was a top of the line intel. I was building a new PC and based on the recommendation of my brother, who was great with PCs, I ordered some arctic silver along with my gear. He had sent me the Newegg link. Unfortunately, I never reviewed the one he chose. So after I got the parts and was building it, for some reason I had to remove the CPU. Well, it wouldn't come off. Turns out he had unknowingly picked out the adhesive cement version of the arctic silver. So, after hours of agony, pain and tempers soaring and trying to pry it off the fan using a few screw drivers, I ended up doing some permanent damage to it forcing me to buy a new one. I think in the process I also broke the MB socket that holds the CPU in place...

It was a nightmare...I should have reviewed his suggestion in the first just to cover myself. Live and learn.”

User “Astranged” made a similar mistake, except with super glue.

On my very first budget build gaming pc: I had an i3-3220 from an old pc, so I had to purchase an aftermarket cooler.. I had a little tube of thermal paste and a little tube of super glue which looked almost identical. I ended up squirting a big blob of super glue all over the cpu and needless to say I spent that day trying to perform CPR on that poor little i3... RIP.”


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GPU Mistakes

Next we move on to the biggest mistakes involving graphics cards, or graphics accelerators if you know your ancient hardware terminology. To start us off, our community manager Joe is back, showing us how not to use compressed air.

“Never air dust your computer while it is running. Seems like an obvious thing, sure. But being tied to your computer, reliant on that connection, it can be tough to bring yourself to turn it off for something as simple as regular maintenance. Thinking, well, I'd like to keep Netflix up and running while I perform this dumb chore, it might not dawn on you to turn the thing off. Lesson learned the hard way.

Those little red pipe sticks you plug into the end of the canned air? Sometimes they shoot off of the nozzle at high velocity. Sometimes they shoot into the spinning fans of your running graphics card, if you happen to try dusting while your machine is on. Sometimes you panic after realizing you've harpooned your very expensive graphics card. Sometimes.”

Our next user, “stuartturner34,” ran into a problem when a new graphics card wouldn’t fit inside the case. Although this is a common problem, the solution is what makes it worth reading. Who needs a bigger case when you own a saw?

“I had an Acer Aspire AX1470d that wasn't running as well as I wanted to in games, so I decided to pick up a new low-profile GTX 750 from Galaxy to throw in there. I figured 'It's a low-profile case, so a low-profile video card should work just fine!' When I actually tried to put the thing in, I realized I'd have to pull everything out of the case, put the 750 in, and then put everything back in the case at once- only to find out that the clearance on top of the case wouldn't fit the card. So, I called up my cousin and took a jig-saw to the top of the case so I could fit it.

TL;DR I sawed the top of my case out to fit a GTX 750.”

Flashing the BIOS on a graphics card can lead to some beautiful results. Typically this means better performance and overclocking, or perhaps new features, but for “alth0triplemadang” it created “art.” I guess it is better to stay positive.

My own biggest mistake of GPUs:

Flashing crappy BIOS update from TechPowerup website for my GAINWARD 9600GT. After flashing the BIOS, now i get a beautiful pattern, lines, and dots with lots of colours! (maybe, i call this as art)

Well... I enjoyed for watching that "art" for 5+ hours while thinking how to fix this! Thanks TechPowerup! you gave me an amazingly destructible "art" for my poor 9600GT! cheers all  i love you tech power UP”

This story from “jeffler383” reminds us that 56K modems are nothing but trouble, but not for the reasons you'd think.

I had a Gateway FX6800 tower that I replaced the HD4850 that came with it with a GTX 460, but because of the 56k modem card in the middle lane (????) it wouldn't fit in the top PCIE slot, so I installed it in the bottom one. It was literally sitting on the floor of the case, and without even thinking about it I fired it up and started borderlands to much improved performance. I was on the phone with one of my buddies telling him how much better this card was when my entire computer shut down. Upon opening the case I was treated to a furnace of hot air and deduced the card had overheated because it had literally no way to draw in air. Once I regained my sanity I quickly discarded the modem card, mounted the 460 in the top lane and fired it back up again. Luckily nothing was damaged and my brother still games on that computer to this day. “

Many of us have wished we could upgrade the graphics inside of our laptops. Most of us don’t buy a graphics card bigger than the computer before realizing we can’t. It’s nice to dream though. Hopefully “roberthop1980’s” friend was the forgiving type.

First fail. Just barely out of HS. Buddy wants to run new game on his laptop (Homeworld 2 I think.) When he goes to install keeps telling him his graphics aren't good enough. Still a newbie enough that I just tell him to upgrade his graphics card even though he can't because it's a laptop.

Comes back from Best Buy about an hour later with a box almost as big as his laptop. Quickly realize that you can't install new video card and return. Friend gave me hell for this for a while.”

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Motherboard Mistakes

It is easy to miss a connection on a motherboard, especially when there are dozens of them. The last thing you want to do, however, is plug something in that shouldn’t be. “UltraXHybrid” did just that when plugging a Molex power cable from the PSU into a Molex fan header on the motherboard. It is amazing nothing was damaged except the motherboard.

“We had everything in place and everything looked fine (After following a YouTube video we had everything set out the same way as the vid) And we tried to boot the PC but... nothing. My brother thought it was the PSU (As it looked as though it had been used before) so he sent it back and got a new one. We then tried again and nothing.

Then after realising. there was a cable to connect the 'Power on' button to the mobo (retard mistake). The PC would then boot for 5 seconds and go off and on, repeatedly. We then realised that the RAM sticks had to be placed in a certain order or it wouldn't boot. Again, 5 seconds then on and off. I then realised the fans were not spinning. So i plugged a fan cable into the motherboard because it fit perfectly and there was also writing where it said 'fan' (This was the worst mistake ever) So after doing that, the PC booted up fine and we high-fived in excitement as we had finally got it working after hours. 20 seconds later there was an orange glow on the motherboard and we switched off the PC immediately. We freaked out and our dad came over and realised what we had done and explained to not put the fans power to the mobo. After turning the PC off, the glow went down and i noticed there was a burnt patch on the motherboard (minuscule burn patch, not extreme).”

You would never think that one little loose screw could cause so much trouble, but it all depends on where it is. If you are lucky, it won’t be somewhere with electricity running through it like it was for “kmiklas.”

“Had a screw floating around somewhere in my case (you can guess where this is going!) It was fine for a long while, until one day I decided to move my rig to a standing position. I Heard that darn screw rattle around and get stuck somewhere. Somewhere behind the mobo, and I didn't feel like unscrewing everything to get at it.

I figured, "It'll be OK." Hooked everything back up, and hit the power button. POW!!! Something on that board went off like a firecracker! I saw a jet of flame shoot out from my mobo, like a little solar flare. Then, suddenly, all was deathly quiet, as smoke and the acrid smell of burnt electronics filled the room. Uhh... it was time for a new mobo anyway...

Sure enough, upon unscrewing that board, that screw fell to the bottom with a pleasant little "clink." Almost like it was trying to apologize for frying my board.”

Falling CPU coolers can do some serious damage. After “thunder_hammer’s” cooler fell and scratched the motherboard, it's a wonder it still turned on.

Most recently - I had to send in my H240-x water cooler for an RMA repair. When I went to put my intel stock cooler back into my PC... I totally forgot about how to install it properly. I didn't move the pins around properly and get them re-encased... So I scratched my motherboard. Even doing some basic repairs from "how to fix your mobo" tutorials... I still have all sorts of problems that I never, ever had before. Looks like I need to buy a new motherboard.”

Building computers can be fun, but I don't think anyone likes connecting the little power switch and front panel cables to the motherboard. They are small, easy to misplace, and if you are like "AMD--Fan," they will end up just wasting countless hours of your time.

"Hello everyone .

Well few months ago , I decided to clean my pc so i removed all of the components . Clean them with an air blower , changed the thermal paste and assembled the computer again but before doing the cable management , i decided to turn on the pc to see if it works fine . I connected the mobo , cpu , gpu power cables . pressed the power button and nothing happened .


Again i removed to mobo , ram , graphics card and tested them one by one on another pc. they were fine . So i assembled everything but i didn't put the computer in a case. used a screwdriver to turn it on and everything was fine, so i put everything in the case but before doing the cable management , decided to see if it turns on again . pressed the power button and nothing happened . I was in a "What ????It's impossible " moment . So i removed everything again and everything was ok and worked fine out of the case so i decided to put it in my case. this time i did the cable management first .

As my routine , the last step of cable management is connecting the front panel stuff . While i was connecting the f.panel cable , i realized that the last times , i didn't connect the f.panel cable and that was the reason that the power button didn't work and computer worked fine out of the case because i used a screwdriver to turn it on out of the case!!!!!!!

loool . I wasted 10 hours on assembling , unassuming and testing the components . only because of a tiny f.panel cable .

well that was my story . I hate front panel !!!!!"

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Storage Mistakes: Stories From The Community

Over the years, data and drive management has become extraordinarily easier than it used to be. It seems like there wasn't much you could do to avoid a drive problem in the 1990s. You had to know how to configure jumpers, cables and BIOS to get the drives running, and then you had to be careful to baby the drives physically, and then in the operating system to be sure your data wouldn't just vanish. Using optical discs and floppy disks were, if anything, more problematic. Because it was so much easier to make a mistake when dealing with storage back then, it is only natural that several of these blunders occurred more than a decade ago.

I'm sure that "ComputerSecurityGuy" was excited to leave this era of problematic storage devices behind, but he first needed to move the data to a new drive. Unfortunately, that doesn't seem to have gone well.

"I was migrating a box of ancient 1.44MB floppies, and I picked up the drive and moved it while it was running. Yep, it killed all the files on the floppy."

Magnets can be helpful, but you shouldn't forget where you put them. Especially not if you are taking out an HDD. I hope you had your data backed up "Ryan_78."

"I had a spare hard drive and I was cleaning my room and put my magnetic tray for screws on it..... didn't see it till 10 months later."

The next submission comes from one of our most active forum moderators, "USAFret." Don't you miss those days when you could completely obliterate everything on your system with the push of a button or by typing "Format C:"?

Windows 98 era.
Wanting to delete everything off a drive or partition.
Select ALL, Delete.

Oops....that was the C drive.
Windows got about 1/3 way through before I saw what was happening.
Oh well, reinstall.
About 5 yrs ago...
Seagate 2TB external drive.
Sony laptop.
Blink, the drive disappears.
Blink, it's back.
Blink, it disappears again.
PANIC...dying drive! Or maybe the enclosure.
Destroy the external case getting the drive out, so I can get the data off it.
Plug it in....copy the data to another drive.
All is good.

No, the drive wasn't dying. Nor was the USB enclosure.
The USB port on the laptop was dying, causing random disconnects.
Still using that drive in my HTPC/house server today."

Optical discs still have their uses, but be careful they aren't too old and worn out. If they are, they might just explode into a million pieces like "jeffler383's" did. I'm amazed the drive worked again. Too bad about the disc though. Baldur's Gate 2 was one of my favorite games too.

"I was attempting to install one of my all time favorite games, Baldur's Gate 2, off the original game CD's I had from back in 2000. I failed to notice that after 8 or 9 years there were several spider cracks on the clear plastic on the inner portion of one of the disks...well that thing spun up and I was greeted to the sound of a CD shattering inside the drive at several thousand rpm. the drive bay wouldn't open - when I took it out of the computer it sounded like a maraca, there must have been hundreds of CD shards inside it. I took it apart and somehow managed to remove enough of the debris to where it would work again, though I wasn't able to get all the pieces out. My roomate at the time got a good laugh out of that one."


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Miscellaneous PC Building Mistakes

Our last few submissions don't quite fit into the aforementioned categories, but are still worth reading. Having come this far, I can't help but wonder how many stories about computer parts bursting into flames or melting I need to read before it becomes routine. I'm starting to think it never will. User "ausskiller" serves to remind us in entertaining fashion by accidentally melting a cable from the power supply.

"In the first PC I built (Celeron 433mhz @488mhz, TnT2 32mb) I made two pretty major mistakes:

When I was first setting it up I noticed there was a port in the back of the CD drive for an audio connector, I found a loose cable that fit and plugged it in. When I went to boot the computer there was a massive puff of smoke and I immediately pulled the plug, afterwards I inspected the PC, freaking out that I had just totaled the PC I poured my lifes savings into, and noticed that the one of the wires of the "audio cable" I had plugged into the CD drive had completely melted off all the plastic coating and when I traced it back to it's source I realized it actually came directly from the PSU  . I decided to tape up the now exposed wire, disconnect it from the CD drive and try to boot the PC again to see how much damage I had done, to my absolute amazement it booted up without any problems, and even more astonishing was that even the CD drive was working perfectly, the total sum of the damage was the plastic coating on a wire, man I felt lucky that day."

There is always a sense of accomplishment when you build a new PC and everything is fine, but when it doesn't start right up things can look dark. When this happens, it is best to check for simple causes to the problem before RMAing parts. Don't be like "KillSwitch07" and RMA half the PC because you forgot about the switch on the PSU.

"My biggest mistake was when i built my first pc (go figure) and built the whole thing, pressed the power button and nothing happened. So i completely took it all apart and rebuilt it. Still wouldn't power on, so i did a rma of the cpu, motherboard and gpu (this was my first pc dont laugh). While i was waiting on the cpu to get back i looked on the back of the psu, and saw the power switch i never flipped."

It is important to keep your PC cool, but it seems "Infikiran" may have taken it a little far. If the force of your fans is strong enough to rip components apart, you might want to get a little worried.

"On my second build I ever did I upgraded my CPU from a Pentium D to a Core 2 Quad 6700. I was nervous at the time to do watercooling so I stuck with air cooling. Still using a cheap case I only had an 80mm slot on the side and a 120mm slot on the back. I successfully overclocked the CPU to 3.0ghz from 2.67 GHz, but here's the issue. To compensate for limited fans for air cooling I bought a Thermaltake aftermarket cooler, "the copper seashell 92mm fan", 80mm Vantec Tornado case fan on the side "6000RPM". and a 3500 RPM Silverstone fan. PC was super loud as you could imagine, but after a couple days I noticed a loud banging noise inside my case.

Powered off the PC and pulled the side off to see that the air current between the two powerful fans and broken the CPU fan completely off and the noise was the electromagnet trying to spin the broken fan. I took the fan off the heatsink altogether and used it as a passive heatsink. Temps were actually cooler after that."

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