1. You can check if the computer id in registration window is same as earlier or if it is a different id.
2. If it is the same computer id click on ‘I already have a key’ and enter the same license key again.
3. If it is a new computer id fill all the details in the registration form and click on ‘Register’. Close the window which is open to enter the key. Click on ‘I already have a key’ and enter the same license key which was being used earlier.