how to reboot when the screen remains blank

[MikeRilling]

Hello,
upon startup - the processor is whirring the indicator lights come on and after a few minutes the fan starts to spin. But the screen remains black - nothing. I was told to try starting it and tapping F8 repeatedly, but nothing comes on the screen. I hooked up a monitor to this machine thinking maybe the screen was bad. Nothing. What's next/

 

[clarkjd]

Do you have a case speaker attached to the speaker header on the motherboard? Do you hear any beeps? (the speaker header is NOT the same as the audio output jacks on the back of the motherboard)

 

[Emerald]

what type of motherboard are you using?