I have an old vaio with win 7 and ubuntu 14.04, with a NVIDIA Geforce 8400M. Now the screen is a mess with squares and lines both in ubuntu and windows. I think the graphic card is broken.
By entering in windows safe mode I was able to unistall Nvidia drivers and now I can enter windows without any problems (I think due to the use of the native intel graphic card). I want to do a similar thing for ubuntu. What can I do in order to use ubuntu without the nvidia graphic card? Thanks a lot.