I have a Sony desktop that won't start. When you turn it on, the light comes on, the keyboard lights flash but nothing else happens. I opened it up and verified that the fan is running so it seems like it has power. It never displays the startup sequence on the monitor (i.e. checking RAM, etc.). Nothing displays on the screen. Could someone point me in a direction of what to try next? I'm wondering if somehow the motherboard went bad and if so how can I verify it?