Computer problem: will power off within a few mins

So to start off this is my first post, I use this site a lot; its fantastic. And secondly I'm not sure if this is the right area to post this problem or if anyone else might know. I can only assume one person out there might know what the issue is.

So basically when I turn my computer on, it will power off without any warning within a minute or two. Very frustrating.

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1. My fan stopped spinning as fast as it should. dropped down to below 800 RPM
2. My CHIP fan for the northbridge stopped spinning so I replaced it with a Zalman Heat-Sink..just now actually.
3. I replaced the fan and now the new one spins faster..though it wont go above 1200 RPM
4.I tried pulling out the DVD drive thinking that there might not be enough power going to everything. but my PSU is 500 watt and should be fine..


It will shut off whether im in the BIOS or Windows. and the temperature seems to be fine around 30-40 degrees celcius.

I don't know what else to say. but I think it could be a problem with the motherboard...or the power supply...

Thanks for taking the time to read this I appreciate any help here. I need my computer back so I can actually keep studying.

Pestilent -

Welcome to the forum and thanks for the kind words.

I've only got a minute right now, I'll have some time later today, but maybe we can start looking at/for some stuff so the other folks here can chime in.

Does it make any beeping noises before it powers off?
What version of the BIOS does it have?
Can you recall anything you changed between when it didn't do this and now?

Hang in there - we'll find a solution...

Check the motherboard for blown or leaking capacitors. Your symptoms are descriptive of that.

http://en.wikipedia.org/wiki/Capacitor_plague

This definitely sounds like a heat issue, but you say that your temps are within normal range ... however damage may have occurred already to the NB before you had time to replace the fan .... Hopefully more will add to this as the day wears on...

Pestilent

Im thinking power config, or hardware issue. 64 bit occasionally has issues with fan control. did this ever work in wi 7

Ken

Another thing to look at is the Northbridge chip - does it have "X 2" on the top? Some of these ASUS A8N-E boards were not built for your CPU, they don't have the "X 2" NB chip, and if it is one of those, it won't run with your CPU. (I have seen some postings that indicate there were those boards for sale in Australia.)

Sorry for the late reply. I haven't had access to a computer for a few days.
Thanks for the reply though

I have a new PSU (Missing a PCI-E power cord though, I think I have an extension) to test my computer with when I get home.

First "TheSchaft":
1. The computer will make no noises once it turns off. it will simply just power down instantly. however the green light on the motherboard stays on.
2. I try to keep the BIOS version current. however it has been a while since I last updated it. I will look this up when I get home.
3. Anything I changed? Well I installed Prototype. and some other programs like Microsoft Project. besides that I don't recall changing any settings. I can only assume that these were the catalyst that broke the camels back.
4. I can check when I get home. but this is what my motherboard looks like if that's any help. I noticed that there are two types of fans, so this might be of help.
Thanks for the help

Now "Torrentg"
The capacitors would be one of the last things I'd think about. thanks I'll have a look when I get home. But I can see how it can make sense..the sad part though is that I'd need a new motherboard

"Tews":
Yeah, at least a year ago my computer had similar problems. and it would turn off from over heating. It may have damaged it back then. though the temperature is perfect. I learned my lesson from that (I think)

"zigzag3143":
Yeah the fans were fine. I had no issues when I installed Win7 originally. though it eventually went below the speed and came up with warnings at boot up. Though I did leave it on for a long time. and a reboot was rare.

Thanks for the help I'll try to get back to you ASAP. I hope it works when I get home. if there are any more problems I'll post them and if everything is fine with this new PSU I'll post it once again.

Ok so I just got home. and put in the PSU (450W). I dont have an adapter for the Graphics card (7800GT) which needs a PCI-E power cord. I tried to run it without any power and the monitor wont show anything. Do I really need power directly to the GPU to see a display? I dont think so.
I tried this before and the same thing happened. any my keyboard(logitech G15) doesnt power on either. nothing seems to work. though it will turn on. and it looks like the fan runs faster now..

Im just confused and mentally exhausted after today. I think I'll just work throughout my break and build a new computer...

Its just annoying that I lack my computer to do my work with.
But if anyone has any ideas I'm more than happy to try it. As long as my HDD is fine in the end I dont really care.