Open the email in which you received your Expert Lotto Pro license.
Right-click the attachment and choose Save as.
A standard window for folder and file name selection will open. Type C:\license.jar into the File name field and click button Save.
Close the Expert Lotto application if it is running.
Start Windows Explorer (or any other file manager). You should see your saved license file in the root folder of your C: drive. Select the file and press Ctrl+C key to copy the file.
Locate the folder with Expert Lotto installation. It's usually C:\Program Files\ExpertLotto on MS Windows operating systems. There you should see your current Expert Lotto Hobby license file. Click the file to select it.
Press Ctrl+V to paste the new license file into this folder. You will be asked if you wish to replace the existing file - choose Yes.
Start Expert Lotto and you should see Expert Lotto Pro in application's title bar and in the About box.