Does it help if you disable the JIT compiler?

• javascript.options.methodjit.chrome
• javascript.options.methodjit.content

You can try to disable other jit prefs a well as a test.

• http://kb.mozillazine.org/about:config

Hi! I just changed both

javascript.options.methodjit.chrome
javascript.options.methodjit.content 

to false. No crashing in one hour. Thank you so much!

By the way is it solution ? I'm not sure.

It shouldn't be necessary to disable the JIT compiler.
Did you try to disable only one of them to see if chrome or (web)content is causing it?

If disabling works then you most likely suffer from a bug.
If you can provide specific steps (STR) to reproduce that crash (i.e. it happens on a specific website) then you can try to file a bug report to see if anything comes up. Without such steps and if no one can reproduce the crash then chances are very low. You can find a link to the crash report page (Bugzilla - Report this Crash).

I was very frustrated because whatever the bug is in my firefox install is, it was causing my computer to lock up sometimes. However, after applying this fix I am now a happy camper. Firefox is now humming along!

Nothing seems to fix this problem. I have the option to loading FF6 or waiting until a solution if found. In the meantime I'm using chrome because FF9.0.1 locks up before I am able to post a reply here.

Chrome ? Are you kidding ? I really hate it! For me there's no internet without Firefox. So I turned

javascript.options.methodjit.chrome to false and now everything is just fine!

You should do the same to avoid crashing. Good luck!