D3D, I tried what you suggested and it seems that the location box in the shortcut's properties is un-editable. The target box is editable and it already contains gamename.exe" but if I try to add the -diag command it cannot find the orginal location.
Felixsg, The other computer has at least directX 9 and I also tried it on another computer running vista, so I'm assuming it could also run my game. If directX is the problem, though, would it be possible to include the updated driver with the game folder?