I have searched most of the forums for Ubuntu but was not able to get the solution of my problem.

I am not able to login into Ubuntu 12.04 through the login screen. I have to use Ctrl-Alt-F1 to enter into terminal and write command
sudo start gdm

And also my Ubuntu is not working in 3d .. It is only opening as 2d
I tried reinstalling unity but it proved useless ...

Please help !!