Random Shutdown Annoyance

[cuttergallery]

My PC randomly shuts down. It doesn't happen every day...it could go a few weeks without happening. However, it has happened twice in four days. I play games on my PC (Half Life 2, Doom 3 etc), but it has never occured during a gaming session. The Event Viewer shows nothing.

SYMPTOMS:
A. I will be just surfing the web & PC will completely shutdown without warning.

B. Thud from speakers, monitor & mouse shut off, but lights & fans in case still on. Pressing power button turns off PC, starts OK.

C. Similar to event B., but pressing power button does not shutdown PC. Have to use switch on PSU to power off. Starts OK afterwards.

I know these type of things are very difficult to diagnose. All drivers & BIOS are up to date.

My PC:
Cooler Master 450W PSU
Shuttle AN35N w/ AMD XP3200+
1GB Corsair DDR 3200
MSI Radeon 9800 Pro
Maxtor & Seagate drives
Aopen & NEC DVD drives
Audigy 2 sound

 

[powerMarkymark]

Have you scanned for Spyware?

 

[cuttergallery]

Yes...Using AdAware, SpyBot & the free MS Utility.

 

[scooter1]

check all the cable connections inside your pc to make sure none of them are loose.