|I think this is the problem we will never resolve. I'm now using Windows 7 too and I have a Radeon 9200 card.|
There is only two way... the first is not to install driver as you did, and although the resolution won't fit, there will be no problems with power functions like shutdown or hibernation (or restart or sleeping).
The second way is to install xp driver from the 6.11 catalyst pack manually. It allows you to set your optimal resolution, however you won't be able to shut down your computer regulary, you will get blue screen. (I've chosen the second one.)
To install the xp driver manually, download this pack, and after it unpack itself to c:\, exit the installer. Then go to device manager, and select "Update Driver Software". Select "Browse my computer..." and set the "ATI" folder on C:\. That's all.
I think the main problem is there isn't any vista driver to radeon 9200.
Hope I have helped you.