Don't use Sony's website for video drivers. Those should ALWAYS come from AMD or Nvidia. Given that Vista wasn't even out in 2005 (it was still somewhat early in development at that point), there is no way that driver you mentioned would work properly. Check www.ati.amd.com for the latest driver (9.8 I believe for the X600).
I got the Vista drivers for what I thought was my Video card from ATI/AMD's website; however, although it appeared that they would work they did not. I believe have the X300 graphic controler card in my Sony VAIO, so I guess I am out of luck. I am beging to believe the MAC commercials about Windows 7! Thank you for your help.