Quote - mousso put the Irradiance cache to 0 not the IDL and your shading rate to 0.2.

Check the "Use own process" too .

I did and still no luck.
As a last resort...I'll do an OS install on the weekend. Who knows, maybe its vista or some driver problem. Its not the first app I cant run on this OS.
Time to move on to windows 7 anyway.