Drivers for ATI

[Mogvet]

I am having problems loading graphics drivers for my ATI Radeon HD 2600 XT. Everytime I try and load it I right click and pick install as administrator in which it goes through all the motions but when I restart it there is no ATI driver installed just the generic VGA driver from Vista. What am I doing wrong????? I have been working on this all day and it's driving me crazy!!! I have DX10 loaded but it wouldn't load them before I had DX10 installed. I have also tried loading just the driver and the the whole Catalist program and it doesn't work. From what I can tell I should have never changed to Vista from XP....XP worked just fine with ATI drivers......