Thank you for posting to the Microsoft Answers Forum.
Try the instructions below:
Go to Start | Search and type regedit. Then choose continue to allow it and then read the help file.
Then go to this registry key
and right click it and choose Export to back it up.
Then make sure WinMail is closed and right click on the key again and choose Delete.
Then try starting Winmail. Go back to your computer's e-mail and open Windows Mail the way you always do.
Please reply back and let us know if this helped to resolve your issue.