OS Blank Screen, no Start up

OK, i just built a new pc and everything seemed to be working fine, unitil i insterted the Windows OS, installed it and rebooted. After it rebooted nothing came up on the moniter, and it doesnt make a beep any more. After looking at the lights everything seems to be on except the system strat up light. All the parts and evrything is compatible, even the ram, type of video card: PCI x16, hard drive, computer box. So now the question is "Can anyone help me resolve my blank boot problem? the coputer starts up, no beep, and nothing on the screen, its completely blank. So what do you think is the problem and how can i fix it.

Set the bios to init AGP port first?

Does the POST screen and BIOS show up?