Hey, first post, in need of advice. So I knocked my tower over with a left elbow by accident, falling off of my desk and onto my scanner. My scanner is done for, but the tower seemed fine - iTunes didn't skip a beat throughout the split-second ordeal. Upon its return to the desk, the tower seemed fine. Then, about 5 minutes later, it shut down. I waited, and restarted it, and it worked great for the rest of the evening. I shut it down before going to bed. Now, this morning, it ran CHKDSK on my Windows-installed drive, C:. It deleted a few corrupt entries, and then started normally. I logged in and let it do its thing, decided to just let it run, and came back about 15 minutes later, and it was on the "locked out" screen. I signed back in, and everything was fine. I opened up My Documents, scrolled down, and then boom - complete and utter shutdown. I should point out that at some point during its construction, I must have gotten a wire crossed, because it will never, ever stay turned off unless I turn the power supply off - if you just shut it down, it will turn on after about 5 seconds. But this time, it stays off. And it actually takes about 10 seconds to turn it back on. Now, I've noticed that the shutdown only occurs when I try to run processes on it. Leaving it idle will net no response, but any attempt to open up a browser or program results in immediate shutdown. I've checked out everything with a mini mag light, and I've had to blow a lot of dust off (it's really dirty, I'm lazy and haven't been cleaning it regularly). There's also a fair amount of thermal paste on the chip, and I'm waiting to get some more thermal grease before cleaning it off. So I think it could be one or more of three things: the C:\ disk is corrupt/cracked/loose, my power supply is shorting, or my chip is cracked. I wouldn't think that thermal paste would be the complete answer, but I imagine if it's heat-related that it has a hand in it. Either way, I'm in need of help. And if anyone knows why the never-stays-shut-down thing happens, that'd be swell too. I should also add: ASRock motherboard, Intel chipset, Western Digital blue caviar HDs, can't remember the power supply offhand, and currently running windows XP.