If you had a prior graphic card installed on your computer, it is very important that you first
remove that card's drivers before proceeding with the new one.
To do so, perform the following:
Go to Start menu> System> control panel.
Click on "add or remove programs"
Choose "Change or Remove".
Then search in the list of installed programs the "NVIDIA Drivers" and click on "Change/Remove".
Click "Yes" to confirm the uninstall. All driver components will be removed from your system.