Firefox crashes when exit or close browser, NAV 2009, XP operating system

When I close Firefox it crashes. I went to live help and even posted a question in Firefox. They tell me you did some kind of update that makes it incompatible. I have a Firefox 3.0.8,  and I just updated Norton from 2008 version to 2009. The 2008 version worked fine. I did it through Live Help. 

  I disabled all add-ons and it still crashed. Then I enabled them all and disabled Norton add-ons, and it was ok. Can I just disable the add-ons, and disable Norton firewall, and use a different firewall?

  I don't really need the add-ons, Firefox is a safe browser and has a lot of free safe add-ons. In IE 8, the toolbar takes a lot of space. If I remove it, does it leave me vulnerable? I don't want any tool bars to take up viewing area on my screen, because then I have to scroll around to try to read things. Maybe if you made an icon instead of a toolbar.

  What worries me is that if I disable it, Norton takes over the windows MS firewall, and puts Norton Firewall in place. Will I be vulnerable?  Can I just use Norton Antivirus without the firewall, and the bells and whistles? <that's a figure of speech>

 

Hope you can help.