03-10-2011 08:36 AM
You could apply a lock to the database.
The DatabaseManager class has a LockDatabase methods that include overloads for informing the customer why the database is locked. This does not block application access, so a user could still launch the application, but would recieve a message when trying to log in.
The only way outside of act that I'm aware of to prevent application access is with the application security tool that's only available in certain versions of windows.