Hi there,
Firstly, this is in the wrong section. You don't have a BSOD. Please have a MOD move it into the right section to garner more responses.
Onto the problem, if you are looking to find the details, the next time FF crashes and shows you the Crash Report Window, click on the Details button to see if you can figure it out and identify the cause.
More here:
Mozilla Crash Reporter - MozillaZine Knowledge Base
And of course, submit the crash details and do a clean reinstall of Firefox. Be sure to disable all add-ons when you do so. Hopefully it helps.