I'm having the same problem
Zotac GTX 260 Amp2
I am using a HDMI/DVI connection
the setup seems right, I have a PC screen, resolution is native 1920x1080 60Hz
but as soon as I start watching movies in fullscreen or switch to a 3D
enviroment szch as a computer game I keep getting that black screen with "NO VIDEO INPUT" or "NOT SUPPRTED FORMAT"
every couple of seconds, it's really anoying