maybe it cud be bcos ur User Profile is screwed up.
uninstall Firefox, and then delete the Firefox Installation folder, the go to C:\Documents and Settings\<Username>\Application Data\Mozilla\ and delete the folder named Firefox
then Run>regedit
delete these entries:
Code:
HKEY_CURRENT_USER\Software\Mozilla\Mozilla Firefox
HKEY_CURRENT_USER\Software\Mozilla\Mozilla Firefox 0.9.3
HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Mozilla Firefox
HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Mozilla Firefox 0.9.3
after deleting these keys, reinstall Firefox, ur problem may be solved
NOTE: i'm assuming u have Mozilla Firefox 0.9.3 installed
Hope this helps