I just got a new PC with XP Pro and SP3. So I installed Firefox 3 and ThunderBird 2 and everything worked fine.
But just recently, when I click on hyperlinks in Thunderbird, nothing happens. It used to open a tab in Firefox. I thought it was related to a new update I just got for Thunderbird.
After trying lots of things (like if Firefox is not running, then the link will work), it seemed like something was blocking it. So I shutdown ForceField, and voila!, problem solved.
Looks like I will be uninstalling ForceField since it doesn't support Firefox 3. I was going to leave it since I figured an update would eventually come, but not if it does damage in the mean time.
Operating System:Windows XP Pro
Product Name:Other ZoneAlarm Product