[tom886]

Actually you can, just don't use the Setup program, select update driver from the Device Manager, browse computer for driver software and select "Let me pick from a list of available drivers on my computer". There select "Have Disk" and choose the directory where the driver was downloaded and unzipped and the Graphics folder.
Windows will probably complain about "cannot verify...." but you are good to go.
Side effect: In the future you can update by the Setup program

Cheers
Tom