ComputerBB

I can turn my computer on but nothing displays on the monitor. All the fans and everything click on but nothing displays. This has happened b4, but last time the video card was a little loose but it isnt this time. I noticed on the motherboard theres a green and a red light. Is the red light supposed to be on if the video card is in, or do the lights have no relavence? Update: Tried using a different monitor, that didnt work Also tried a different video card, nothin.