Computer crashing

If it wasn't a major problem I wouldn't ask for advice. As for taking it to bestbuy or another place, waste of money. I already know that I need to replace something, but I'd rather ask people who don't cost money what it is. Also, they'd probably fix it without asking first and then be like "Well we're gonna need you to pay an excessive amount of money for something you could have done yourself for free and cheaper!"

In order for them to fix it without asking, you have to sign some paper before hand saying that you want them to look for the problem, and that you agree to pay for parts and labor for the repairs. Look for the part about them fixing stuff, cross it out, and have the service rep and youself initial it. That way when they fix it anyway and try to charge you you can sick your lawyer on them .

Personally, I couldn't say what your problem is.

It's either your power supply, your video card, or you're getting heat problems.

The first thing you should try is flipping the voltage switch on the power supply to the other setting, then flipping it back. When you push it back to the original setting, put some pressure on it. This sounds stupid, but it fixed a problem of mine once.

If that doesn't fix it, try to boot and go into bios. Check your processor temperature. Are you running an AMD or Intel processor? They run at different temperatures.

Also, you could try another video card if you have access to one. If you're using AGP (likely) you could also try a PCI card (in case it's your AGP slot on your mobo).

There's really not much else that can be determined until you try some things. Give that a go, and post your results.