That only appears to be an issue with some people who are running the game full-screen in Windows 7. 
I had the same problems with my brandnew windows 7 pc and DirectX 11 
Changing the DEP solved this problem, Barbara described how to do this in   
this thread  Thanx again Barbara for all your help, you're amazing    
 You guys are so busy right now, solving all those problems and issues with all the different systems ...
you need AND deserve a huge break after getting VV4 out!!!