About 10 months ago my powersupply burnt up, so i recently bought a new one. I've had no problems with it, but i put it in a firewire card to load some video onto my computer, then 20 minutes later my computer shuts off. My fan warning noise goes off and I see my psu fan is not moving. Anyone know why in the world this would happen? Any help would be great

Fans die. I've lost a few PSU's over the years and in each case the PSU fan had seized up. You can try to replace the fan or buy a new PSU.

Michael J

Fans are often cheap quality and they often die all of a sudden or get stiffer and stiffer, I had one where I was using the computer and a clicking noise appeared , then no noise and I found the fan had broken in half.
If stiff to turn you can sometimes get working but accessing the fan, peel the sticker off the centre which often reveals the pivot, spray in a little WD40 (in UK, might have different name in USA), and keep spinning it until nice and free, and hope it did not burnt out when stuck. New fan best but depends if you are 500 miles from civilisation or not.
**The inside of a PSU can contain dangerous voltages - you must be VERY CAREFUL **