Windows 7 - Picture cuts out and crazy graphics when switching to full screen

I have Windows 7 Pro x64 and am using WMC. I have it hooked up through a Yamaha RX-V765 to a Pioneer Elite Pro 110FD. When I start my computer, after the initial Windows screen and also when I switch back and forth from WMC full screen and Windows, the graphics go crazy. Going to WMC full screen, the picture goes black and crazy colors and horizontal lines flash for a few seconds, goes black, picture comes up, goes black, then comes up and stays up. When switching from WMC full screen to a windowed view, the screen switches to the top half WMC full screen and the bottom half windows, with lines going through and flashing, then the picture drops out, comes back, drops out, then comes back and stays. What the hell is going on with my system? Bad video card? bad driver? bad system memory?

Any help would be appreciated