Ok first off I'm an AMD tech head, if this was an AMD board I'd have lots of ideas but because my friend was talked into Intel (over my objections) I'm taking a stab at fixing his box.

I've worked on this machine before but the last time I think it was just a heatsink that was solid with dirt that was causing overheating I blew it all out and it started running last time. The current symptom is the machine starts, runs about three minutes then shuts down.

I pulled the fan off the cpu, it was already loose two of the screws were not tight (what a stupid way that works on stock intel 775) the idiot that put it together had used the stock heat sink pad and it was all crusty and stiff and broken up so I cleaned all that off and put on some amd heat sink paste (the white stuff, had artic silver but this guy is such a cheap wad I probably won't get paid here so I'm not wasting my good stuff on him). Pulled the cpu out of the socket sprayed it with crc put it all back, still have the issue so I illiminated that (or I think I have, I suppose the fan or the cpu could still be bad). Put a different antec power supply in the case, still does it. The machine was running fine until someone bumped it when it was running, now it does this. I am thinking shorting issue someplace but it really doesn't act like that because it does run it just is shutting down rather quickly.

The tight wad won't pay for an OS he's using an old copy of windows 2000 it's mostly used as a internet browser for the people staying in his rooms. It gets just past the initial load screen, where the white line fills across the screen then just goes off. I notice the fan takes a few seconds to spin which is why I'm thinking it may be bad most modern boards will take steps to protect the system if it thinks the fan isn't running (some more ridiculous about it than others).

This has a pcie video card on it, I suppose something might be going on when the card switches into higher quality mode, next idea is to try swapping the video card and maybe try just booting with one hard drive in case one of his ide burner/players has gone south and is sucking too much power or something, I did swap out the cmos battery because I know those can cause all kinds of issues when they're dead.

Looking for ideas because my instincts are pretty good with AMD setups but I have almost no clue about how to deal with an Intel based setup.