I have this problem on al Dell Inspiron 9400, too (edgy and feisty kernel). My solution was to boot the kernel 2.6.17-9, which works or to deactivate WiFi (ipw3945) in the bios.
-- CPU soft lockup during bootup https://launchpad.net/bugs/63418 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
