hi pyramid14, we have seen quite a number of similar reports about this issue in the last hours and this issue is likely caused by your symantec security software that is hooking into firefox (probably through a program/signature update done by them). other users reported that updating firefox in this situation helped with the crashes. you can download & install the latest firefox from https://download.mozilla.org/?product=firefox-48.0.2-sha1&os=win&lang=en-US - xp sp3 is still supported!

Thank you! Symantic had, indeed, done an update this morning. Version 48 loaded but a new question--I'd saved my default profile before uninstalling. How would I reclaim my (many) bookmarks.

Thank you again.

for that please see Recover important data from an old profile

Thank you. I've gotten everything back. I recall now that I stayed with Firefox 40.0 because a couple of years ago Norton was incompatible with v 41 so I'd prevented updates since then.

I'm now better off than I was.