Dirt 2 Not Working! :(

[Maniacfest]

Managed to get a free copy of Dirt 2 with my i7, which I successfully downloaded from steam. It was fine until about a week ago, when I went to launch it and it would not go past this screen:

and the exicutable stopped responding. Anyone else had a similar problem and managed to fix it??
My Specs:

Asus P6T
i7 920
Nvidia 8800GTX (Don't laugh, will soon be upgraded!)
Corsair XMS3 16oomhz memory

Cheers, James.

 

[MeMeMeMe]

Maybe: When that happened to me, I had to download the latest update to GFWL and install it, before starting Dirt 2.