I had got into a serious problem while solving my the system is running in low graphics mode using this link.

This guy and I have almost same Nvidia card. Mine is just bit more newer, so when I was on step #13 I completed it and rebooted my computer and my screen resolution got shrinked while my problem has not solved instead I have lost my unity and all can see is a blank screen with only my destop icon and shrunken screen in center. I get unity back when I remove the nvidia-current package

My actual problem was that when I boot Ubuntu I get a screen saying:

The system is running in low graphics mode. Your screen, graphics card and input device settings could not be detected correctly. You will need to configure these yourself.

and I was able to login after few tries.