Try this: Get a piece of wood, lay the motherboard on it (yes you remove it from the case first). Reseat the CPU + Memory. Re connect all power connections to mobo and the mobo to the power switch of the case. Connect the video to the onboard video (what sort of connection is this? DVI? VGA? HDMI?) to the monitor. turn on, do you get BIOS? Try a different monitor? Still no joy?