according to my dad, his computer was working fine he got up and left for a sec and came back in time to see it go dark and turn itself off. Now it wont power up at all, there is just a green light on the mobo and the screen says. "please check signal cable" is the mobo screwed? i tried pulling on the memory and turning it off with the switch on the back. and it doesnt beep but....i dunno if that means anything scince nothing turns on at all except a little green light on the mobo.