> My desktop went tits up today and I'm trying to figure out what went bad.
>
> I was watching a flash video when the system turned itself off and rebooted.
> Ever since it hasn't worked right. The computer will turn on (fans come on, the
> system beeps, the HD drive light flickers a few times), but it won't boot and my
> LCD screen keeps saying "No Signal". I tried swapping out the graphics card,
> but that didn't seem to make any difference.
>
> Could it be the hard drive?

Well, I suppose there could be a small chance. More likely it's something with the motherboard, processor, or possibly memory. It might've taken a shot while you were away.

My box started acting up like this occasionally after I dropped a Barton into it at its normal clockspeed. 98% of the time, it's OK. Occasionally it won't POST (just like yours is doing), but most of the time a reset will snap it out of it's fugue. Once every month or so it'll stay comatose for a half-hour. Reboots, all bets are off. I have to leave it off for a while before it'll come back. Once in a while (usually after some hardware or BIOS change or if I'm not careful and hibernate or "sleep" my computer instead of regular shutdown) it'll hang at the DMI Pool Update just before passing to the bootloader.

Pretty much all these problems go away if I underclock my processor, but I didn't buy a Barton so I could run it at T-bird speeds.

Basically, see if you can't get it to boot again. If you can, slow your processor down and see if the problems don't go away. If you can't, pull the boot drive and see if it won't boot on a similar system (at least that way you'll know whether the drive is bad).