I know it's not a Windows problem, because the same thing happens when I hit Delete to enter the BIOS. Whether I'm in BIOS or Windows, once I tap the Digital/Analog toggle button and the monitor goes into Digital mode, the monitor displays the contents again for about one second.
This problem started when I entered the Performance Test mode for Devil May Cry 4. I'm not sure if it's a video card problem or monitor problem. I don't have spares of either to test, so I'd like some ideas before I go and find someone who can help me.
(I have an nVidia GeForce 8800 GTS and a 19" Samsung Syncmaster 940BX LCD monitor, if that matters.)