I have seen some questions like this but I thought I might be able to provide more detail.
I recently installed Ubuntu 11.04 and wiped 10.10. Since my old built-in graphics card is incapable of 3D acceleration, I tried using Ubuntu Classic. After logging in, I was greeted by a choppy background and flickering menus. (I have NEVER had this problem in Ubuntu 10.10). So I even tried logging in using Ubuntu Classic (No effects), the screen was much better this time, but the panels were a little messed up and it crashed on me several times after a few minutes.
I have a Pentium 4 2.66 GHz. 1.5GB RAM. Built in graphics Intel Extreme Graphics 2 96MB memory (I think it's shared not built in memory).
Is it a problem with my graphics card or driver?