I just performed a clean installation on my Computer, and it stuck on the loading screen at first startup. However, the terminal still works. I have tried update the graphic drivers (nvidia gtx 760), but it did not work. What should I do?
I am assuming that you trying to install Ubuntu 12.04 LTS base on the tag. I had a similar issue. Try executing the following.
Sudo apt-get install xserver-xorg-lts-precise
I also have documented few more tips here.