Thank you for the response.  I looked at both ASUS and Nvidia for the 174.31 drivers that you noted but they are not posted for the 8800GTX, I think that it said that the driver 174.31 is for the new series 9 card.  Please advise

 and thank you for your assistance!
GanjaStar Wrote:bonediggy1031 Wrote:Hello all,
I have an 8800GTX with the latest drivers installed from ASUS (169.21) and Penumbra: Overture AND Penumbra: Black Plague give me the error at startup that my graphics card does not support vertex shaders.  I just got these games so I would really like to play them and any help would be greatly appreciated
   My OS is Windows XP Pro if it helps and I did patch the games.  Thank you for any help...
I have the same card and both games work flawlessly, try 174.31 drivers. And Do not touch shader options in riva tuner if you did that.