You can always download Mockups 3 for Desktop here.
The license is tied to you, so you are welcome to install your license on both your current laptop and your PC Desktop (and any other computer you use regularly). You can read more about this here.
To move your license to your new machine, you would select the “Help” menu and then “Unregister from this Computer,” and then install the program on your new machine.
Finally, we wanted to just mention that we released Balsamiq Wireframes for Desktop, our new major version update, on January 15, 2020.
The cost for new licenses remains the same and the update cost for Mockups 3 for Desktop licensees will be 50% of the regular price.
As usual, updates are not required, and you will be able to continue to use version 3 if you don’t wish to purchase a major version update. We have some additional information here: https://balsamiq.com/wireframes/desktop/sales/update/
I hope this helps Razka, if you have any other questions for us, you can reach us at firstname.lastname@example.org.