Today I've upgraded the system and the problem is that it appears and 640*480 screen with the login and the background, after logging in, the screen got stuck.
I have an NVIDIA card, GT610 to be precise, and I have CUDA installed, this is necessary because I'm learning to develop on this. So I followed the CUDA Ubuntu 14.04 Official Instructions. Which are to install a deb package, and then do sudo apt-get install cuda. This installs nvidia-340 and cuda-6.5
Everything was fine until the upgrade, what can I do to fix this?
PS1: I've been looking for answers(reinstall ubuntu-desktop, reinstall unity), and no one seems to fix the problem.
PS2: I have a PC Intel Core i7-3770 .40 GHz, 4 GB RAM, NVIDIA GT610.
EDIT 1: There was another update today, I tried it, I repeated the uninstall-install and nothing happened
sudo add-apt-repository ppa:xorg-edgers/ppa
then runningsudo apt-get update && sudo apt-get install nvidia-340
. This should allow you to install the newest version of the nvidia-340 drivers. Normally, this is a last resort measure, but you appear to have tried everything else