i recently built a pc for my friend using parts he gave me, the system turns on fans spin, leds are on etc. but when hooked up to a monitor it says no signal. i have tried reseting cmos and the graphics card, ram, etc work in my system but not his. it doesnt have a os because its new but bios doesnt even appear. ive tried multiple monitors same no signal on all of them. think the motherboard is fried? or is there an issue with the power supply? could it be to low of a voltage that the computer just wont boot up?