PC is not turning on

[_SunTzu_]

my bro turned off the pc (so he says) i tried turning it on, it doesnt turn on ... its hooked in the plug, my optical mouse's light is lit so i dont think its a power supply problem, i tried taking out the RAMs, blowing the dust off of them and their sockets, switching their places, i even tried unplugging the power button and plugging it again in the motherboard, still nothin ... when i push the power button just nothin happens. my pc used to turn on for half a second then turning off when i plug it, but now the half second second boot doesnt occur anymore.
any help on what to do?

Thanx in advance

 

[halister_one]

It could be something got fried, like PSU or mobo. The only way I see it is to use a different PSU and try it out. There wasn't any smoke coming out of the PSU, was there? Or any burnt smell?

Also check the wiring that connects the power button to the motherboard. Perhaps the connection got loose or dusty.