i need to ask a computer related question.

What'd i'd do to check if its overheating is take the damn case off. Just unscrew the sides and top or whatever, and remove them. Then boot the computer (or however you rigged it to work) Then hit * del * and go into CMOS. Then go to the right side, its like (Hardware monitor , or some shit) and It'll tell you a few things that you need to know.

You should be able to see how hot your computer and CPU are running. I think the max temp the computer is supposed to be is 113 F. Mine runs at about 138*F and has had some of the same problems as you've been having.

What my teacher has told me to do if your having possible hardware problems, remove all excess shit you don't need.
Modem
NIC card
any other bs you don't need, etc

Thats if you can't boot at all.

You may be using too much power for your power supply, you should find some of the manuals for each of components you have in your computer (Video card, Sound card, CPU, everything.) Get the watt requirements and add them up, make sure your power supply can hold all of them.

But what I did to fix my problem which was similar to yours was just format the HD. I don't know why, but my computer was doing the same shit as yours (Locking up, having bullshit errors all the time) But I don't recommend doing that. I could get onto my computer for about 20 minutes and it'd lock up. Reboot, repeat.

Taking off the case isn't going to help a processor overheating problem. There's simply not enough air flow to prevent it. He needs a new CPU fan to fix that.

It's also not a wattage problem unless his power supply is going out. Guess what. It's not his power supply. He already tried a swap.