Yesterday when i turned on my computer, i heard a weird "grinding/buzzing" noise. I thought the nosie was comming from one of the fans, so i checked them all, but i think the noise was comming for the power supply. After about 1min the sound went away, so i didnt worry about it. This morning when i turned on my computer, it did it again....but while the windows screen was loading, the whole comp. just shut off. I then try to turn it on...but i get nothing. !! what is wrong!? ...is that a sign of a dead power supply ? what are some ways i can test this? ... I have an Asus A7n8x mobo. and they have a green 'activity' LED at the bottom, (and since the computer just shut off, it has not lit up) ..what can i do, to figure out what went wrong. Asus A7N8X Deluxe 2.0 ATI 9800 Pro AMD Barton 2500+ 1024 PC3200 Ram 120gig Maxtor HD Audigy 2 420 watt psu

It could be just a bad PSU fan or the whole PSU. Easiest would be to replace the PSU. I swapped a PSU fan recently and it was a lot more monkey work than replacing the PSU. But, if your PSU died beacuse the fan wasn't working, it may already be too late.

Sounds like a bad idea, I wouldn't open that PSU up if you don't know what your doing... you may very well die. =\ got sleep?

The PSU should be unplugged. Usually, the cover is held on by 4 screws and a label that voids your warranty when broken. The fan sits in back and will have two wires, usually black and red, that go down to the circuit board. They are usually soldered in. Cut the wires as close to the fan as possible and strip the insulation back on the wires coming from the circuit board about 1/4 inch. Most PSU fans are 8 cm. Remove the four screws holding the fan in place and position the donor fan in place and screw it in. Strip 1/4 inch of insulation from its wires and twist the red wires and the black wires together. At this point, I will BRIEFLY and CAREFULLY plug the PSU in to see that the donor fan is blowing OUT of the PSU. Then unplug the PSU and solder the wires together, tape the soldered connections, stuff the wires carefully back into the box so that they don't cause any trouble, and replace the cover to the PSU. See, a lot of monkey work. But, I did it on an old AMD K6 II computer a couple weeks ago and it left me with a great deal of satisfaction. And, since it was an AT MOBO/case, replacing the PSU would have meant tearing it up to replace the power button too.