Computer shutting down for no reason

[Max_Alloy]

A couple of weeks ago, my computer started powering off for no reason. I built it last summer and its run perfectly sense then. No recent additions of hardware or software. Sometimes it would stay on 3 minutes, sometimes 3 hours, sometimes 3 days. I suspected either MOBO or PSU problem, so checked the connections, cleaned out dust, etc.. It worked again fine for a while then this morning powered off again. I checked connections etc. again but it would only stay on for a few minutes at a time, and finally would not boot at all. I cleared CMOS and tried again, still no boot.

What could it be?

Here's my system

2GB DDRII RAM 533 mhx
Gigabyte GA-M55plus-S3G motherboard
350 W Antec PSU
300 GB Seagate hard drive
AMD Athlon 64 2800
DVD/CDR combo drive
nVidia 7600GS video card
on board audio

Thanks

 

[michiganteddybear]

Well, the computer will NOT shut down for NO reason, or fail to turn on for no reason either. Either something has failed, or there is an error in assembly (depending on circumstances, the latter only applies to new systems, or systems being repaired).

I would suspect power supply first. That is the most abused part in most systems. when you figure its gotta take all that nasty ass power from the utility (find me an outlet, not protected by a UPS or other conditioner, that has clean power, and I mean CLEAN power, reliably, and I will kiss your feet!), and turn it into clean, stable, regulated power for the pc to use.

they get the crap kicked outta them all the time.

 

[sweetpants]

Another thing you can do, just to make sure, strip everything... leave nothing plugged in except for the CPU, and PSU. Then try to turn it on, see what you get... if you get nothing... you narrowed it down to PSU or motherboard, if you're not getting a light green light on the motherboard I'd read your manual to find out what that means and replace accordingly. If you're getting a green light and still no post either processor or motherboard I'd assume.

 

[Techfan]

I'm a computer technician and i'll give you my advice based on my expiriense in the field. I used to have several customers with similar problems like yours and the reason was the PSU. Just throw it in the garbage and buy a new one. Don't try to change anything else you will waste your money and time. I repaired more than 10000 PCs till now and the only reason caused such problems was PSU.

 

[sweetpants]

I'm a computer technician and i'll give you my advice based on my expiriense in the field. I used to have several customers with similar problems like yours and the reason was the PSU. Just throw it in the garbage and buy a new one. Don't try to change anything else you will waste your money and time. I repaired more than 10000 PCs till now and the only reason caused such problems was PSU.

I'm also a tech, and I'd suggest narrowing it down. Granted it's most likely a PSU issue, there's always that one time it isn't and you'll end up kicking yourself because you wasted MORE time and MORE money than would have been spent had you just troubleshot

 

[nobly]

Recommend trying to swap the PSU or get a PSU tester. It could be other things, but PSU is at the top of the list as the culprit. I recommend doing it SOON, as a blown PSU could lead to blown parts...

 

[Max_Alloy]

Thanks for all your advice, guys. I have a body that can test the PSU (most likely culprit) and we'll go from there. Frankly, I've always felt a little underpowered with 350W -- my power usage calcs show me at 300+, pretty close to the edge for a pretty cheap PSU to begin with.

I'll post the final solution.