Computer Boots but No Display

BrokenPC

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Mar 19, 2014
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Hi,

I recently had an error message while using my PC along the lines of "system recovered from nVidia graphics failure." Meanwhile, I was getting pixellation and screen blips. Then my computer would reboot. After a few instances of this my PC now boots (I get a beep) but I get absolutely no output to my monitor. The only way to shut it off is to flip the power switch at the back. The standard power switch only reboots after holding it down.

I have tried removing my graphics card and using the onboard graphics, but it doesn't make a difference. I can only assume it is my motherboard or CPU. Help!
 
With "no display" issues, the most common problems are, in this order:

RAM
PSU
GPU
Mobo
CPU

Take out all but one RAM module. Power on the system. Do you get a display? If yes, shut down and move the RAM module until either you've successfully booted into Windows and have used all DIMM slots; or until you can no longer get a display.

If you don't get a display, turn off the computer. Move the RAM over to the next DIMM. Repeat until you've tried the RAM in all DIMM slots; or until you see a display.

Either of three things will happen:

1. You'll test all of your RAM and find that one or more modules are bad; or

2. You'll test all your RAM one or some, but not all slots are bad; or

3. All slots are bad.

If testing RAM finds that all are ok, move on to PSU. Test the PSU by using a digital multimeter. Use the link in my signature to find the nominal readings from each color wire.

Next on the hit list is CPU. I've seemingly skipped to CPU because you've already ruled out GPU, and the RAM testing I asked you to do will determine if the RAM or the mobo is deffective.

Edit: Remove the CPU cooler (A.K.A. Heatsink and Fan). Clean with 97+% Isopropyl alcohol, and then reapply thermal paste. Alternatively, you can swap the CPU with a known working one if you can get your hands one another.
 

BrokenPC

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Thank you. I tested one RAM module in each of the four slots. None of them resulted in me getting a display. Should I try the other modules in each slot or move on to PSU?
 

Redheadsrule13

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Oct 25, 2013
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Try every RAM module in every slot. Then go to the PSU.
 

BrokenPC

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I am now strongly suspecting the power supply as the fan is not working. I have a spare, although it is a lower wattage (380 vs. 500). Any reason not to switch them out?
 

Redheadsrule13

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Not really. It really depends on how much power your system needs. You can still use it to check whether the PSU is the problem all the same, just don't do anything too power intensive just in case.
 

Redheadsrule13

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Okay, it's either the motherboard or CPU now. However it's worth double checking that you have your monitor plugged in properly and set the the corrent input. Plus check all the plugs on your motherboard. Never hurts to double check.
 

BrokenPC

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Mar 19, 2014
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I have already tried using a different monitor (that was one of the first things I checked). I can't actually change the input on my monitor unless it is on and it won't turn on without an input, so I can't check that easily anyway.

I ordered some thermal paste, so I'm going to try cleaning the CPU and heatsink next, but it might take a few days to get the thermal paste. In the mean time I cleaned out the CPU fan, which was pretty caked with dust. I don't know if cleaning it would have any effect, but I figured it can't hurt.

I do have a CPU from an older computer, but I'm a little hesitant to swap them out for fear of damaging it. I'll take a look later today and see if it's something I think I can do easily enough.

 
If your CPU fan was "caked with dust" it could be that your CPU overheated. Unfortunately there aren't any tests you can do, except to swap your CPU with a known-working CPU. Just keep that in mind as you're ruling out possibilities.

Also, while you're waiting on the thermal paste, try breadboarding. Although this display problem is resulting from a fresh build, a short can still be a possibility.

To breadboard:
1. Unplug everything from the back of the computer
2. unplug everything connected to the motherboard, except the CPU.
3. Remove all of the motherboard screws, followed by the motherboard.
4. Place motherboard on a non-conductive surface (phonebook, wood, cardboard, etc.)
5. Reconnect the PSU and install one RAM module.
6. Using a flathead screwdriver (or similar metal tool), touch the "+" and "-" PWR_SW pins on the motherboard.
 

BrokenPC

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Mar 19, 2014
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Well, I feel foolish, but it looks like it was my video card after all. With some tinkering I found that the reason I didn't detect this earlier was that my monitor also was unplugged.

Thanks everyone for all your help and sorry for wasting your time.

Now, does anyone have a video card they'd recommend? Something reliable preferred :)
 

BrokenPC

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Mar 19, 2014
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Okay. Strangely, I replaced both my power supply and my graphics card. My computer was working fine until I installed the driver for the graphics card. As soon as I did that and restarted my computer it went right back to the old problem of no display, reboot beeps happening every minute or two, and the only way my computer would turn off was if I shut off the power at the back. So I'm back to thinking something is wrong with my motherboard. Any ideas?