I`m sure you know that: perspective before reinstall windows. Did I backup everything? Or something would get lost? And what about mails & accounts data? Before you reinstall system (if, of course , you want to save your data mail, accounts and addresses from Thunderbird):
1. Make backup folder:
Documents and Settings\user_name\Application Data\Thunderbird\Profiles
(to view all files you should switch to show hidden files in windows folder options).
2. After installation a new copy of Thunderbird put all saved data to the same location as above.
3. Edit file:
Documents and Settings\user_name\Application Data\Thunderbird\Profiles\profiles.ini
add part with your profile, i.e:
Default=1 mean this is a default profile
4. Run thunderbird.
5. Have fun 🙂