I was trying out a full version of Avast Internet Security and at the end of the trial time, it began unloading the full version of the software. While it was in the process, it came to a point in which it asked to reboot the computer. I clicked yes. At this time, Firefox was in mid bootup and Firefox Browser has crashed every time since this event.

I have deleted Firefox several times and reloaded it and it still crashes. I did a virus scan and found not problems.