NEED HELP WITH COMPUTER SHUTDOWNS!

[swz]

ok i don't know how many people actually read this but here i go

specs:
athlon xp 1700+
alpha heatsink
antec led cpu fan
cpu temp: 31C
CHA temp: 32C

mobo: soyo dragon+
lian li pc60 case
512 crucial 2100
300 W PSU
system: 1.5 years old
-------------------------------

THE PROBLEM: runs normally then out of the blue, computer shuts down spontaneously.
- no virus, no backdoor found through homecall free online virus checker, mcafee, or norton
- temperature stable
- i have 1 video card and 1 cdrw, 1dvd. so i don't think 300W is too little. (i have been running a similar setup for 1.5 years now)
- reinstalled windows XP from scratch

SYMPTOMS
* sometimes after computer has crashed i would NOT be able to start my computer. meaning i'd push the POWER ON button and NOTHING WILL HAPPEN. then i wait a little bit and for some miraculous reason it works again...
* the system has been rock solid until i switched hard drives...i got a new seagate barracuda...currently using it as my secondary (non-OS) drive

help please...

 

[microAmp]

Have you tried a different power supply? A quality one?

 

[howdyduty]

Try to up the voltage slightly on the cpu, the ram, and/or agp. That often adds stability.

 

[Ape]

PSU may be going. Its probably overheating. Make sure the PSU fan is spinning at a consistant rate. Ape Out.

 

[Looney]

Yeah, sounds like the PS is going.