I've been having a persistent problem with my Kubuntu 12.10 system locking up, although fortunately the lockup isn't totally solid. I think it has to do with a stopped script in Firefox. Here's the Firefox message:
Does anyone know why this is happening or what I can do to recover from it when it happens?
A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.