No display on screen.

Hello,

Hello,
ut no image on monitor. Computer starts up, power supply fan works, CPU fan works, Attatched side panel fan works. Lights light up, Drive sounds as if working, Boot sounds to start working (no 'beep' though).... but NO image. Monitor says it's working fine, check connection. Well Connection is fine. What gives? Can't check BIOs if I can't get an image. Is there any one out there who can help???
thanks in advance.