same issue here. my problem didn't arise til i installed my nvidia video card. used a month before that with no problem.
dapper, recently installed nvidia, k7 kernel -- Xorg process freezes, uses 100% of CPU. Can be killed by remote terminal. https://launchpad.net/bugs/51991 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs