I've noticed some posts from people having serious problems with Firefox. My advice is to completally uninstall any Mozilla related software ex. Firefox, Firebird, Thunderbird, and Mozilla itself if installed. Once you have everything uninstalled try installing just Firefox itself fresh. Try it out and then work in reinstalling the rest. I do not advise using Firebird with Firefox on the same system. They all use the same code and can sometimes conflict from older versions to newer versions. This will probably not work with character conversion not transfering correctly but should fix any other serious issues.

For those of you wanting to try linux you should look into Ubuntu http://www.ubuntulinux.org/ . It is fairly easy for new people to install and you can just use add/remove programs to install more software if you so desire. It preinstalls both Thunderbird and Firefox. It also updates automatically (like windows autoupdates) and updates fairly frequently.

The people that make Ubuntu will also send you a free cd if you cannot download and burn your own.