Hardware Help!

what power supply do you have?

might want to try this next time your computer is on, take a tooth pick (very important that it's a tooth pick, otherwise u might not like the out come) touch the center hub of the fan inside your power supply, you should be able to do this form the outside of the case without opening it, if you can feel some major vibrations then you might have a bad power supply fan...

also might want to pull the mains plug (that goes to your wall), get a flash light and look at the connector on your computer. see if it's discolored.. and try swaping the power cable with the one that goes to your monitor

also could be a hard drive or other disk drive overheating / shorting..

might want to check that out