I've had this problem for about a month now. It started when I put in a new Processor a few weeks after my old one died. When I turn the computer on, with the monitor hooked up to my Video Card, the screen stays blank until it reaches the Windows Logon Screen, then it is fine. It is the opposite with the onboard, it will turn on through the boot until the Logon Screen, and then it goes blank. Appreciate your help in fixing this! Thanks.