Akin to this problem is one that I have encountered when I tested a program on a friends computer with dual monitors. The CountGFXMode3D() returned 0 even though he has a NVidia 6800. CountGFXMode() returned the correct number of modes, but GFXMode3D() returned False for each mode. He can play 3D games just fine, as well as run LightWave (a modelling and CGI program). I'm curious if Blitz is incompatible with dual monitors.