I had installed Ubuntu 12.10 yesterday but it was not working properly, so installed Ubuntu 12.04 from Live USB and after installation, it was working without harm, but problems arose when I installed updates, the screen is going weird if I launch dash home.
I've posted link of screen shot of my screen, hoping that this problem can be solved. http://samsher.xtgem.com/pics/problem.png Take a look at top of the screen, there you can see the problem.
lspci -nn | grep VGA output
00:0d.0 VGA compatible controller : NVIDIA Corporation C61 [GeForce 7025 / nForce 630a] [10de:03d6] (rev a2)