Get the most up to date Nvidia drivers at
http://www.nvidia.com/page/home
Use the drop down box to choose your video chip set or card and get the latest drivers. Put them on a reserved folder on C:/
Next, start your computer in safe mode so it loads basic horrid looking drivers. Then uninstall any Nvidia drivers you have and install the fresh drivers downloaded from Nvidia.com. Remember to check out Windows update to get any new drivers or patch updates.
To uninstall your driver find Device Manager (Control Panel - System or similar, depending on your Op Sys). Select the Nvidia adapter and uninstall it by right click - remove from system. Then do a refresh and it should plug & play and find it and ask for the drivers. Select the "specific location" option and "Have Disc" button and drill down to the files you downloaded from Nvidia.
I Hope this helps to solve your problem.