I had a fully functional Ubuntu 11.04 installation on a Gateway LT3103u netbook. I upgraded to 11.10. When I logged in, the screen was all strange: instead of a pointer there was a large pixellated square, the desktop was a series of horizontal and vertical lines, and text was garbled. I used ctrl-alt-1 to use the tty and installed the xubuntu-desktop package on the theory that perhaps the problem I was having was Gnome-specific. Now, however, when I boot the machine, I can't use the mouse on the Ubuntu login screen or after I log in. What do you suggest I try next to approach this problem? Thanks!
Update: Answer to the graphics problem.