This may not be the most professional advice but, sometimes Windows Update gets it messed up. You could try a direct download from NVidia:
1. Download the drivers from NVidia
NVIDIA GeForce GTX 460 >>>
2. Uninstall
any present drivers
3. Reboot
4. Install the package from NVidia
5. Reboot
Between 2 and 3 a registry check / fix could be wise, although these checks have been questioned by many. I've used
Free Window Registry Repair: a windows registry repair freeware. for many years, no problems. But I don't really have the expertise about it.
Hope you get it running.