Bootcamp trackpad drivers for windows 7 seem to get overwritten.

I'm running windows 7 ultimate on my macbook air 13", partitioned with bootcamp 3.2. I've installed the windows 7 bootcamp drivers and applied the track pad settings, and they work correctly for a while, but then they seem to just vanish. I go back to bootcamp and the tab for track pad settings isn't there. This seems to happen about once a week. At first I thought that windows updates were overwriting the bootcamp drivers, but I've disabled automatic windows updates and the problem still persists. If do a repair install of the bootcamp drivers, it works correctly for a a while. But as I said, I have to reinstall about once per week.

Any suggestions?