Do a clean reinstall and delete the Thunderbird program folder before reinstalling a fresh copy of Firefox. Download a fresh Thunderbird copy and save the file to the desktop. **http://www.mozilla.org/en-US/thunderbird/all.html Remove the Thunderbird program folder before installing that newly downloaded copy of the Thunderbird installer. *It is important to delete the Thunderbird program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling. Make sure that "remove personal data" is NOT selected when you uninstall Thunderbird as that will remove your Thunderbird Profile Folder with your personal data. A good place to ask questions about the Thunderbird program is at the MozillaZine Thunderbird Support forum.<br /> That forum is better suited for questions about Thunderbird, this forum is aimed at support for Firefox. * http://forums.mozillazine.org/viewforum.php?f=39 * http://getsatisfaction.com/mozilla_messaging/products/mozilla_thunderbird