Please Help- Steam Version Theatre of War Kursk

[Feros1]

Hello all, I recently installed all three Theatre of War games from Steam. The only one that works is the first one: Theatre of War. When I click on Africa or Kursk a brief box pops up from Steam saying its starting and nothing happens. I have tried all possible fixes, compatability mode, etc, what could it be? Any help greatly appreciated. I have Windows 7 64 bit, ATI 5870 2g HD card with latest drivers, ASUS p6Deluxe Motherboard, 12 mb ram. I uninstalled a re-installed Thanks!