It is strange that you encounter this behavior. Probably the application did an update and needs to be re-activated. To do this, you need to re-enter the activation code that you previously used. If you can't do this, try performing a fresh installation of the program. Before you do this, it's advised to remove the old copy from your system by going to Start > Control Panel > Programs and features. If you still can't use the program, contact the developer on the official website.