[kubuntu] Vertical lines after upgrade

This is a weird one. I did an upgrade from Kubuntu 12.10 to 13.04 on my Dell 1501. When I did a reboot, all I got were several vertical lines on the screen made up of different colors. After about ten minutes, the screen blanked, and when I moved the mouse, my log-in screen appeared. I logged in but it took a very long time for the log-in process to take place. After that, everything seemed to be OK but loading some programs takes much longer than normal to load.

I thought it was a driver issue, but the only driver suggestion is for my wireless.

I've tried different loading methods (nomodeset for one) and nothing changes. As it is, it's serviceable but not useful.

Thanks for any help or ideas.