I was working on one of my friends computer, an old hp pavilion and it won't turn back on. im guessing all i have to do is reset the mobo but im not sure where the switch is or if there even is one for that matter. the power supply starts up for a second, fans go and such but then it cuts off. i know it's not the power supply or chord because i tried two others and same result. sry i don't have the exact model but could anyone help me with this?