In ACT! 2007 and greater, login as a user who is an Administrator.

1. Choose Help > Register ACT!
2. Choose the Add button.
3. Choose, “I have already purchased a license”
4. Type in the serial number.

Troubleshooting:

You are using Windows Vista and you want to add another ACT! serial number to the database but Windows tells you that you do not have permission.

1. Close ACT!
2. Single right mouse click on the ACT! icon and choose “Run as Administrator”
3. Login as an ACT! Administrator

You should now be able to add the serial numbers.