L'un des premiers posts, épinglé par valve :
Exit Steam entirely.
Browse to your Skyrim installation folder (Usually C:\Program files\Steam\Steamapps\common\skyrim\)
Run the following installers:
...\Steamapps\common\skyrim\DirectX10\dxsetup.exe
...\Steamapps\common\skyrim\DotNetFX\dotnetfx35set
up.exe
...\Steamapps\common\skyrim\VCRedist\vcredist_x86.
exe
Reboot your computer and test any issues again.
Essaie ça.