I've been experiencing the same problem with linux-image-2.6.15-25-686. After I upgraded from 386 to 686 with linux-686-smp I've been having system freezes when browsing the web with firefox. It doesn't happen all the time, but it does happen randomly. And, yes, the only thing I can do to get things working again is doing a hard reboot :(
* Using Intel P4 3.0Ghz HT * Problem also is occuring with the standard "nv" drivers -- system freezes after last kernel update https://launchpad.net/bugs/50323 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs