Assassins creed and Crysis error

[Koloss]

I installed Assassins creed 1 and crysis. Both games worked fine with XP. Then I installed windows 7 .Now when I run Crysis I just get black screen and assassins creed just stops working in first 2 seconds.
when i run task manager, its not responding.
I tried to update drivers.
I have dx11.Is that problem?
all other games work fine
I noticed that assassins creed 1 and crysis are only games i have with one .exe file for dx9 and one for dx10.Maybe that is connected with my problem.
Please Help!

 

[vierasniper]

reinstall them, also patch the games to the latest patch

 

[AstaLaVista]

That and if and when it ask you to install DirectX, let it install it. You will not suffer from it and the games will run better

Also, update your Sound & Video Drivers from manufacturer and Not from Windows Update