I just installed 12.10 on my PC, no problems with the installation and it seemed fine. For a while... At intervals, I get a "kernel panic" and the system reboots after 30 seconds, after which is is fine until next time. There doesn't seem to be any pattern to this, and I can't identify anything that triggers it.
I did a google search and found some suggestions that it might be a memory problem, so I ran the Memtest86 utility that is accessed from the grub menu. Once it got to test #7, it started giving lots of red error messages. So I thought that's it, I have some bad memory. However, I ran other versions of Memtest86 (from various Ubuntu alternate install discs, openSuse liveCDs, even the standalone version, no memory errors detected.
I've attached a photo of the error message (not very good, taken with phone, but legible I think).