Firefox keeps freezing and using 50% cpu and memory usage shoots up real fast and carries on going till it uses up all there is left. Most of the time it's when there's an auto update of anything addon, plugin or ff but not just neccessarily then! I find out it's happened when there's been an update after i restart and an extra webpage comes up with the particular addon/plugin/ff update. I have to restart most of time because nothing sorts it out. I'm using windows xp with the latest update of ff 13.0.1 it's not this version because it's been happening for a while. And it never started when i added a particular addon or plugin or when i added a new app to my pc either. Any idea as to what this may be or how i'd sort it out?

Cheers