Ubuntu 14.04 Screen Freezes Randomly with NVidia and it is possible to fix with Ctrl + Alt + F2 then Ctrl + Alt + F7

I had EXACTLY the same problem with NVIDIA drivers.

Your problem probably is related to these bugs (they all have the same symptoms):

https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-319/+bug/1220426
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1310762
http://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1314871

Unfortunately it is not solved yet.

If you have an optimus capable card, the solution I've got to be able to use the dedicated graphics card while mitigating the problem was through the installation of bumblebee with primus.

Just do this on terminal:

sudo apt-get install bumblebee bumblebee-nvidia primus

When you need an application to use the dedicated graphics card, you can issue a command like:

primusrun steam

I had the same issue using the NVidia 331.340 driver.

It seems like the NVidia driver conflicted with my Elan touchpad..

For me, using an USB mouse just fixed the issue.

If the drivers available through Ubuntu don't work correctly, you could try finding your driver on Nvidia's official Unix/Linux driver's page.

TL;DR

Updating to latest driver solved the freeze on Ubuntu 14.04.

I have NVIDIA GeForce GT 550M.

$ lspci | grep -i vga | grep -i NVIDIA

01:00.0 VGA compatible controller: NVIDIA Corporation GF116M [GeForce **GT 550M**] (rev a1)

After upgrading from Nouveau to Nvidia, Ubuntu 14.04 kept freezing. The video alone would freeze, the audio for instance kept working. I figured that I had "nvidia-340" package installed from ppa:xorg-edgers/ppa.

I queried and found I had nvidia-340 installed

$ dpkg -l | grep -i "NVIDIA binary driver"

rc  nvidia-340    **340.96**-0ubuntu0.14.04.1  amd64        NVIDIA binary driver - version **340.96**

Queried cache and found a later one (352.63)

$ sudo apt-cache search "NVIDIA binary driver"

nvidia-340 - NVIDIA binary driver - version 340.96
nvidia-340-updates - NVIDIA binary driver - version 340.96
nvidia-352 - NVIDIA binary driver - version 352.63
nvidia-352-updates - NVIDIA binary driver - version 352.63

Googled "352.63 nvidia"

Visited the Nvidia site http://www.nvidia.com/Download/driverResults.aspx/95159/en-us

Navigate to "Supported Products" tab, it had my Graphics card. Then run following commands:

sudo apt-get install nvidia-352
sudo apt-get install nvidia-352-updates

No more freezes so far.