Had the same problem, nothing would load, and I knew that the program had worked a few months before when I tried the demo.
Windows updates, video driver updates, virus checks, registry scans,re-installation of video pad, nothing worked. But then I started noticing lockups in flash, and bad 3d frame rates in other programs.
Hate to be the bearer of bad news, but what ever the problem was, it was my fault, some unknown change I had made since a few months ago, as I re-installed windows, and now the program works like a dream.