Hi, a few weeks ago I came home a few hours after having used my computer in the morning to find it off. It would not turn on. I unplugged everything and took off the side panel and found the PSU still warm. I read around on similar postings on this forum and decided it was my PSU. I bought a new one. Still didn't turn on. However, the f-lock led on my keyboard was lit up when the switch on the PSU was flipped on. So I e-mailed my motherboard company, Epox. I recieved some directions that would get rid of electricity still in the board such as holding the power button down for 10 seconds, setting the cmos to 2-3 for a few seconds and putting it back onto 1-2. One of the directions was to remove the round cmos battery, which i did not do because I was unable to reach it enough to remove it. I also took it completely apart and replugged everything in. No such luck. So, I bought another mobo, one just like it but the chipset was nforce3 250 instead of nforce3 ultra. Supported the same hardware, though. Still will not work. So, now i'm wondering if it's the power button on my case. I am probably going to plug my friend's case's power button into my mobo and see if it turns on. >>>>To summarize- 1)Computer mysteriously turns off. 2)Buy new PSU. 3)Fiddle around with old mobo, but end up buying new one. 4) Still will not turn on. And when I say won't turn on, i mean nothing turns on, moves, makes noise, or lights up. System Specs: EPOX EP-9NDA3I NF3250 939 (mobo) (Original one was an EP-9nda3J, not I) AMD athlon 64 fx 3000+ venice 2x512 dual channel corsair DDR400 RAM 80gb western digital SATA 150 HD PixelView GeForce 6800 GT 8X AGP XFinity 500 watt PSU If you have anything at all to say or suggest, thank you so much. If not, thanks for taking the time to read all that!