A long time ago, Pinnacle Support gave the following steps for completely nuking a database and starting over:
(1) Deinstall the ShowCenter software and reboot.
(2) Go to Control Panel-Add/Remove Programs and uninstall the Microsoft SQL Server ($PINNACLESYS). Reboot again.
(3) Go to the ..\Programs\Microsoft SQL Server folder and delete the $PINNACLESYS directory here (if it still exists).
(4) Reinstall the ShowCenter software.
Drastic, but should work.