I am moving into a new win 8.1 laptop from a dead win 7 laptop. Win backup could not find the profile on the old hard drive. I installed Thunderbird on new laptop and set up my email. I copied both old and new profile to a thumb drive. Tried to replace the new withte old profile and it did not work. Then tried uninstalling TB and re installing it but each time I do it will not launch; says something is missing.