Disabling preferential device drivers
By default, Windows Vista will prefer a device driver from Microsoft rather than from a third party vendor if both drivers are available for the same device--even if the vendor's driver has a more recent version number or creation date. This could mean that you are not getting the latest drivers for your hardware if for some reason Microsoft doesn't have the latest drivers available from the device's vendor. You can disable this behavior and force Vista to always install drivers based on latest version number or creation date by editing Local Group Policy as follows:
1. Type gpedit.msc in the Start Search box and hit Enter.
2. Click Continue when the UAC prompt appears.
3. Navigate to the following policy location: Computer Configuration\Administrative Templates\System\Device Installation
4. Enable the following policy setting:
Treat drivers signed by Microsoft the same as those signed by others
Note that this policy only applies to signed drivers, which are always preferred by Vista over unsigned drivers.
Cheers, Mitch Tulloch, MVP http://www.mtit.com