Got home from work, PC turned on fine... Keyboard and mouse didn't work. Shut it off, now it won't power back on. I hit the toggle switch on the PSU, and my LED fans flash on for a half second. Is this the psu or mobo? Don't have another to test with...
Nevermind, fixed it. Here's the odd thing. I found another power supply.. Plugged that in, worked. Plugged the "bad" PC back up, it powered right on with no problem. Thoughts as to why that happened? Mine is that the power supply is on its last leg...
Problem still exists. And I'm not sure why no one's replied yet. Again, I power on the PC, keyboard/mouse don't work. Plug another PSU in, it works, PC powers on after replugging the current PSU in (not the tester). Only powers on once. So basically, each time I want to turn on the PC, I Have to plug a PSU from another PC into it, replug the original back in, and turn it on. What is going on?
The PSU is probably too saggy to keep your box up. When you plug in the other PSU, it gives the capacitors on the mobo enough charge to boot once. When the PC is shut down again, the caps drain and the PSU doesn't have the chutzpa to boot it from a cold state. In other words, replace your PSU, before it fries your hardware!
^a powersupply that does not have enough juice to power a system would have a low probability of frying anything when it finnaly goes. But i agree, replace the psu. By looking at your rig a corsair 450vx would do perfectly. But i do have to say, in your sig it says sata3, lol there is no such thing yet. There is only sata 1 (which is 1.5gb/s) and sata 2 (which is 3.0 gb/s)