Can you Boot into safe mode ?
As I understand your OP; it worked until you installed new drivers ?
In safe mode you can change or remove drivers.
Re-download your drivers
http://www.evga.com/support/download/showdlinfo.aspx?id=10586&type=N&acctype=Driver&accversion=368.39&part_number=GeForce%20700%20Series%20Family us.download.nvidia.com/Windows/368.39/368.39-desktop-win8-win7-winvista-64bit-international-whql.exe
What is the part number and brand of GPU you installed ?
Which output are you using ?
What monitor are you using ?
Have you tried a different cable from GPU to monitor ?
Does the cable fit snugly on both ends, are the ground/ retainer screws attached ?
Go OFF line for security; close ALL background software even security software, then install the drivers.
Choose custom install, only select PhysX and video drive !
DO NOT install GeForce Experience, 3D or sound - you can install them later if you really need them
As previously mentioned check your BIOS settings.
You should check that your MB, BIOS is up to date (read the mfgs note on any newer version of your BIOS) if the above does not resolve the issue.
Good luck, let the form know how you make out.
Good read - release notes
http://us.download.nvidia.com/Windows/368.39/368.39-win10-win8-win7-desktop-release-notes.pdf
post edited by Cool GTX - 2016/07/04 14:50:36