you need a driver
removal tool to completely get rid of all nvidia graphics drivers
on your machine before redownloading and reinstalling the driver again.
This one seems to work well Guru3D - Driver Sweeper (Setup) download from Guru3D.com
Guru3D - Driver Sweeper is a fast tool to remove driver leftovers from your system. It's very important to remove your drivers on a proper way, because driver leftovers can cause problems like stability and startup problems. You can use it if you want to update/remove drivers from your system. Driver Sweeper 2.6.0 features a lot of additional entries compared to the previous version and improves most removal methods.