yea, u replaced the supply, then its def. mobo. thats too bad. and somewhat ridiculous that you can't find a replacement for a 4200+ :(

def. disconnect everything from the machine, as per the previous post. i would also unplug the power supply from the board, and hold in the power button for about 10 seconds. plug the supply back in,...

seen it many many times b4.

make sure you put ample paste between the cpu and sync, i've seen the exact same issue when that happens. also, remove the graphics card,, and try and use the on board. after you've done that, if it...