Open the Personal Address Book
double click on the recipients name
Uncheck Always send to this recipient in Windows Messaging Rich Text Format
Close the Options window.
1. Download and install the Office 97 Service Release 1 (SR1)
2. Download and install inetmail.exe that updates Outlook 97.
3. In the E-mail box, double-click the e-mail address. Clear the "Always send to this recipient in Windows Messaging Rich Text Format" check box. This has to be done each time a message is sent via the Reply button.