Can you open "about:crashes" in a new tab, and check whether there are reports corresponding to the timestamps when you experienced the problem? Have they been submitted?
Did the problem start happening just after installing a firefox update? (i.e. were you using an older version before yesterday?)
Can you open "about:crashes" in a new tab, and check whether there are reports corresponding to the timestamps when you experienced the problem? Have they been submitted?
Did the problem start happening just after installing a firefox update? (i.e. were you using an older version before yesterday?)