No Video

Here is a question for all the hardware guru’s. Before I ask thequestion let me tell you what I have done. I have replaced the RAM, CPU, Motherboard, switched from a AGP to a PCI video card, switched power supplies, and have reloaded Windows 2000 and XP multiple times. Okay now for what’s happening. When I boot the computer the screen goes blank after the now starting Windows 2000 (or XP). The OS continues to load in the backgroup, but with no video. Does anyone have any suggestions.