I'm using the latest nvidia driver, I've tried various versions, old and
new and it's the same thing. After a day or two, sometimes sooner, X will
only refresh a window if I focus to another window and back. I have to
restart X to have a working Desktop. I have done various searches but
haven't stumbled on anything so I figured I'd try posting here.

Ubuntu 9.04, Nvidia 8800 GTS