I don't really understand why windows would continue to overwrite your driver unless it thought there was something wrong with it.
Have you tried rolling back the driver? Maybe uninstall the device and let windows find it then reinstall your driver.
Is there a setting in your bios for type of video card? Have you tried changing the "is PnP OS installed" to no, or yes depending on what it is now?
There are procedures for installing a driver package in the archive. You can find out which install package is being used by opening Device Manager, going to Device properties of the adapter, Details tab, click on property to open the list and look for Inf name about 30 up from the bottom. That will say oem12.inf or something like that. You might need this information if your problem continues and more procedures have to be accomplished.