buddy disconnent ur moniter wires from motherboard nd then plugin ur
moniter power supply to power socket then check whether u r able to see
any display if yes then ur motherboard is culprit else

ur moniter has
gone .
i got the exactly same problem motherboard was the culprit in my case it
breakdown while i was playing "unreal" cos of heat ( my cpu was not properly
ventelated )
hope this will help