Hi AlanOSWW,

Usually the only reason it will ask you to reboot is if there is a file that must be modified that the updater doesn't currently have access to. You should try running the Firefox program once as Administrator:

• Right-click the icon and choose Run as Administrator

If that doesn't help then do a clean reinstall.

1. Download a fresh copy of Firefox from the Mozilla download page and save the file to the desktop.
2. Uninstall your current version of Firefox and remove the Firefox program folder before running the new installer.
3. Run installer

Remember that you don't want to remove personal data when uninstalling. That way you'll still have your personal information.

Hopefully this helps!

Unfortunately running unistall still brings up the reboot message

This fixed it for me- one simple file deletion:

http://kb.mozillazine.org/Browser_will_not_start_up#Computer_must_be_restarted_message_after_Firefox_upgrade

If you see a message similar to Your computer must be restarted to complete a previous upgrade of Firefox after a major update (e.g., from Firefox 3.6 to 8.0) and restarting the computer doesn't help: On Windows, open the Mozilla Firefox installation directory (e.g., C:\Program Files\Mozilla Firefox or, on 64-bit Windows, C:\Program Files (x86)\Mozilla Firefox) and delete the file "firefox.exe.moz-upgrade", if found. Alternately, do a clean reinstall (use another browser to download the Firefox installer ) and, after first removing the Mozilla Firefox installation directory, reinstall Firefox).

Thanks for your suggestions; have tried both but still getting restart message