DirectX 10 is built into Windows 7, but the Witcher is DirectX 9. If a game was not programmed to utilize DirectX 10, then it won't run with any DirectX 10 features.
thx man,yeah i read my dxdiag report and win 7 has dx 11 built in. not that any games or programes that i know of that utilize 11 yet. good to be ready though!. i do have one question thoe, does a game like cryostasis sleep of reson, the only dx 10 title i have atomaticly run in 10! because i only get the icon for dx9. my card is dx 10 compatible, nvidia evga 8800 gts sc640. so des it run in 10 out the box,since my card is dx10? thank you.