The latest version of Firefox is 1.5, which fixes a lot of bugs, includes automatic updates from now on, faster browsing, etc. I too noticed that a few times using previous versions, but it hasn't happened since I upgraded.
Hope this helps,
P.S. For more comments, check out the post you made in the Computer Help forum.
I'm using Firefox 1.0.7 and most of the time it loads flawlessly. However, at times when I click on the icon to open it up all I get is an hourglass that flashes constantly but the browser never loads. In task manager I notice cpu useage going to Firefox. So far I've managed to correct things with a system restore for my XP version of windows but I'd really rather find the reason and correct it and not have to restore so often. Any thoughts or suggestions?