You can try simulating a clean install:
Move the "%APPDATA%/VoiceAttack/" folder and its contents to a safe location(your desktop will do). The "VoiceAttack.dat" file is the main database that holds all your profile information, with the copies in the "Backup" subfolder holding previous iterations.
The settings for the application are kept in "%LOCALAPPDATA%\VoiceAttack.com\". This also contains your License information(if you have one), so if this is deleted you will need to re-enter it. Move this as well.
Starting VoiceAttack now should run it as a demo version with default settings.