What was the Nvidia Driver Version that you installed? I've seen a lot of users having problems with the newer 190 series driver. Most of the problems are with SLI but I have seen some single card users experience simular problems.
You'll need to download Driver Sweeper.
Guru3D - Driver Sweeper (no installer) download from Guru3D.com
This is a zip file, just unzip the files to a location you'll remember.
And download the Nvidia 186.18 drivers
NVIDIA DRIVERS 186.18 WHQL
Restart to Safe Mode.
Go to Control Panel\ Programs\ and uninstall the Nvidia Display Drivers and the PhysX Driver.
Go to the Driver Sweeper files and double click Driver Sweeper.exe
Select Nvidia - Display and Nvidia - PhysX
When it's done look in your Program Files (x86) Folder and delete any Nvidia Folders you find.
Go to your Windows\System32\ folder and delete these files if present.
Were almost ready to restart. But we don't want Windows Update to reinstall any drivers so remove the network cable or disable your wireless adapter before restarting into Windows.
Install the Nvidia 186.18 drivers
Restart, enable your network adapter or plug the cable in.
When Widows loads go to Windows Update. Check for Updates. The Nvidia Driver should appear as an Optional Update. Right click on the Update and Select Hide Update, Exit out of Windows Update