Shoutbox

I've had those problems before... Are you using the Tabbrowser extension? It's known for causing trouble. What other extensions do you have?
Try a full uninstall (see below), reinstall it and be careful with which extensions you install.

To uninstall Firefox completely, do the following:
- Uninstall Firefox from Add/remove programs.
- Remove the folder in which it was installed.
- If you're using Windows 2000/XP, go to Start > Run, write "%appdata%" and press Enter.
- If you're using Windows 9x, go to Start > Run, write "C:\WINDOWS\Application Data" and press Enter (change C: with your Windows drive, of course),
- Delete or rename the Mozilla folder.
- Now you can reinstall Firefox.