On the software-CD you got with the GM-counter, go to the folder specific for your product and look for information about the PRO-version of the software, in the text file there is a PayPal-link to purchace the PRO version at a discounted price. The serial number of your device can not be used to register the software, you will recieve a email with the registration code during business hours (i.e. no mail if you buy during weekend, you'll have to wait until monday (I think anyway)).