The GCode Sender 4-Axis software license is bound to the computer's CPU that will be activated for the first time.
The GCode Sender 4-Axis requires a different license for each PC. To be more precise, it requires a different license for each CPU. This means that if you activate a license on your laptop you cannot transfer it to your desktop just by transferring the software files. To transfer the license you must also transfer the processor from one computer to another.
Now you will be thinking "Should I buy a new license if I format my computer or if I change the operating system ?" The answer is NO. You DO NOT have to buy a new license because each license is bound to the CPU of the computer.
For more questions like this check the GCode Sender 4-Axis FAQ
To activate SourceRabbit GCode Sender 4-Axis click on the Activate-->Activate Online menu and open the License Activation Manager. Fill in the email and password of the SourceRabbit Account you used to purchase the license and then click the "Activate" button (as shown in the image below)
After purchasing a license from this website, you have the ability to manage your licenses from your User Account. See the screenshot below