I had put in a new video card on the box and tried installing nvidia drivers version 173 via command line and System ➜ Administration ➜ Additional Drivers.
Now when I try to restart ubuntu 11.04 it is starting in command prompt mode.
What can I do to fix this or get the things back as they were?

startx? In the past when my boot has failed to start graphics, I found simply typing that to usually be a quick and simple solution. – WarriorIng64 Jun 28 '11 at 4:56/etc/X11/xorg.conf? Try moving it away and reboot (sudo mv /etc/X11/xorg.conf{,.back}. – htorque Jun 28 '11 at 6:17