This question already has an answer here:
I installed Ubuntu 12.04 today. Everything went fine. I booted the computer, the password screen appeared. I entered the password and pressed enter. However the desktop never initiates. It freezes in a black screen, and sometimes a error message appear saying that the application Compiz has closed unexpectedly. I'm really eager to start working with Ubuntu, so all help would be appreciated. Keep in mind that I don't have much experience with Ubuntu. Thanks. D.