Finally got my 'good' PC back together this week. This is my Gaming, Video/Music editing machine as well as the place my IPOD music library lives (I hadn't updated the IPOD in a month!). Last year it went Kablooey, the power supply caught fire, burned the mother board a bit, but it still worked when I put a new PS in. Then it went flaky two months ago, so I bought a new PS and that worked for a month, and then THAT went funny. I figured the slightly toasted motherboard may be the culprit, so I bought a new one, and that worked for two days, then it went kablooey again. I thought PS. I don't have a ton of spare parts for P4 boards (mine required a minimum 350Watt PS) so I took it into PCCyber, as it was under warranty(even though I slapped it together myself 2 years ago!(grin)). They checked it, said it was fine, I tried another MB, same story.. Swapped it for another, same thing. Then I tried a new PS and WAMMO! It started to work again. Those &^%$*# at the computer store lied to me! Well, not really, they just neglected to plug the 4 prong power cord that gives the processor extra juice and I'm pretty sure THAT was the wonky part. When you plug it in and give it juice the MB doesn't post, no video and it makes a sound like a drive spinning up, like a capacitor charging (even though there are no moving parts (when the fans are disabled) on an MB.
It had me going for awhile. I thought I turned stupid when it came to troubleshooting hardware probs. The techies at the computer store assume that as well, until you strip the MB down in front of them, isolate it on a static bag and then start the MB with a screwdriver across the HW Reset pins and then they start to listen to you a bit.
Morale of the story. If your Motherboard has burn marks on it, you should probably stop using it. And if you isolate your MB on a static bag then it ain't a grounding issue. I hate computers sometimes.