Comment 5 for bug 1447838

I've had a very similar experience with the upgrade to 15.04 with NVIDIA GTX 960. I've just completed nearly 24hours of troubleshooting. I got around my NVIDIA problems here after a fresh install of 14.10 and some steps I found here that helped. http://ubuntuforums.org/showthread.php?t=2263316 see also my additional steps at comment #7
I see there are problems with many NVIDIA cards and I don't want to keep posting this for each driver.