If there is nothing showing in Control Panel/Add or Remove Programs (XP) or Programs/Uninstall a Program (Vista/Windows 7) to uninstall it there, then try the following:
Go to Start/Run and enter regedit hit the Enter key.
HKEY LOCAL MACHINE/SOFTWARE/MICROSOFT/WINDOWS/CURRENTVERSION/UNINSTALL
Look for any entries in that key that pertain to CA, SBC or whatever the anti-virus is/was called, and delete them. be very careful to only delete those entries and none of the others.
Other than that contact Technical Support Chat via the Useful Links above.