This was wierd more than stupid, although with the sheer number of systems I wrecked that day... I felt pretty dumb.
So I am working as a tech at a local computer shop one day on a machine that simply didn't respond (other than fans) when the power button was pushed. It had a slot 1 proc (this was around the time that these were on the way out) and I needed to test whether it was the processor or mobo. I take a new slot 1 processor, put it into the machine. Nada. Ok, the mobo must be bad. So I take the board out of the system and put in a new board with the old processor. Nada. Umm ok. I then take the new processor and put it in with the new mobo. Nope. Just wow. We only had a couple of boards in the office at the time that would work with that particular cpu... one was the new board that I had tested initially with, the other one was a board that was fairly new in the machine that my boss was using. So I take both cpu's and ask my boss if I could try them in his machine. He agreed... and I first tried the new proc. Nothing. grrrr. I then tried the old cpu. It failed as well. Scratching my head, I reinstalled his old processor into his machine, hit the power button, turned and went back to the bench. As I am looking at all of this stuff trying to figure out wth is going on, I hear "What did you do to my system?" from my boss' office. It had now died with the same problem. No boot.
The fix for both my boss' system and the problem computer was to entirely replace both cpu and mobo.
so..
New CPU... fried
New Mobo... fried
Boss CPU... fried
Boss Mobo... fried
I guess the one nice thing was that those cpu's and mobos all were RMA'd.
Oh yeah, and after taking the mobo out of my boss' system... it made a tingling sound that varied in pitch and volume as you moved it around. FREAKISH.
I think after all was said and done the diagnosis on the original system was demon posession.