Computer comes out of standby and sqaushes video to left half of screen

[Todd33]

The screen is readable, but all of the video is on the left half and the rest of the screen in blank. I can then choose a diff res and go back to the original (1920x1080) and all it well. It never did this before I switched to my 7900GT from my old 7800GT. Is it a BIOS thing? Any ideas?