Computer locking up after replacing power supply

I'm having a very strange problem with my computer. The other day I went to
use my computer and it wouldn't turn on at all. No fans, no beeps, nothing.
However the light on the motherboard was on. Some searching revealed that the
likely problem was a failed power supply so I got a new one. Both the new and
old power supplies are 500 watts.

So I hook everything up and the computer starts up fine and resumes my
previous session (it was hibernating before I replaced the power supply) but
locks up after about 5 minutes of use. The power and reset buttons don't do
anything. So I turn off the computer from the switch on the power supply. But
now the computer won't come on again.

I come back after about 30 minutes and try to turn it on again and lo and
behold it starts up. But this time I get some weird error at startup about
how overclocking has failed and the BIOS settings have been reset to default
(I have never overclocked my computer). After this it boots to Windows. But
then it locks up after about 15 minutes. I manually shut it off again and it
won't come back on.

So 30 minutes later I come back and it turns on and boots to Windows. This
time I clean my registry to see if that helps and restart the computer. It
seems to work fine for about an hour and then I leave to go do some things.
When I come back I see a blue screen. So I turn it off again and of course it
won't come back on.

When I can finally get it to come back on it works fine for about 5 hours
with no problems and then I shut it off for the night. The next day it still
seems to be working fine but then it starts locking up after a couple of
minutes after it boots to Windows.

What could be the problem???

Have you tried resetting the BIOS to safe values?
Are All the fans working smoothly, including the new PS?
Did you look for bulging caps on the motherboard?

On Sun, 17 May 2009 16:54:21 -0700, Steve Urbach


I forgot to mention.
Check the CPU fan/Heat sink MOUNTING integrity.
It can easily take a hit removing the old PSU and crack or the (yuck!) thermal
tape become damaged.
---
Printed Books don't become obsolete,
Their contents may just become out dated.
Save the print book, say no to DRM.

On Mon, 18 May 2009 08:26:10 -0700, dragonsclaw@mindspring.com.invalid
wrote:


Another possibility is the CMOS battery could be dead/dying. If the
OP usually just hibernated the PC instead of completely powering-down,
then it's possible that the CMOS could be maintained using the standby
power from the power supply even if the battery is dead. Replacing the
PS would have removed that standby power.

Mike

Sounds an awful lot like an overheating problem to me. If a friend has a
working power supply, even if it's not as powerful, I'd borrow that and see
if the computer functions well with it. If you bought the new power supply
locally, and it's under warranty, I'd take it back for an exchange. If you
bought it from NewEgg or the like, return it by all means for a new one.
HTH, JG