I apologize, I am very new to ubuntu, and not sure how I even got to this mess, but I hope someone can help

I had the os up and running well, I came home And noticed the unity. Launcher missing, so I went to restart the computer and noticed updates, and updated then restarted.
On restart, it worked, but the graphics were all off, attempted nvidia x settings, and received an error message, sorry I don't remember wait it said, so I downloaded and installed new drivers.
On reboot now I only get "ubuntu 12.04.1 LTS myname MS 7673 ttyl
Myname-MS-7673 login:" at the top of the screen, and don't know what to do, please help

O