I have a cumputer that I just put a new motherboard,and cpu into.I turned on the computer and the board and fans and the cd-rom drives work,but I can't get the monitor to show me anyhting.I have 512 ram installed,tried installing the new bios cd but can't get anything to happen.what am I doing wrong?

Could be anything, you need to provide more details, like any beeps? LEDs are on? etc.