Outlook email signature font keeps changing

This user has Vista as her o/s and running office suite 2003. She has her email signature setup with Comic Sans 12 font blue for new messages, replies, and forwards. She has also indicated “use my fonts” and uses word as her defualt editor. When she tries to create a new message or reply to a message the font switches back and forth from Times New Roman to Comic Sans and sometime it’s a combination of both fonts and a comination of the color blue. Help!