Computer locks up and needs reboot

I installed Norton Online Family and the Minder, and everytime I launched FireFox, my computer locked and I had to reboot.  I am currently running FF 8.0.1 and Windows Vista Home Premium.  I am not sure if the same symptom would be evident with another browser, as I did not try one.  I un-installed both and FF works normally again.  Any ideas where to try troubleshooting?