If you have already activated your Windows 10 once, Microsoft remembers the product key tagged against the device id. If you don’t want to have 2 partitions, you can remove the partition and freshly install the Windows 10 Home edition by downloading it using the Microsoft Media Creation tool found below.
https://www.microsoft.com/en-us/software-download/windows10
Follow the below steps to create the installation USB and to perform a fresh install of the OS. You can delete all the partitions in the dialogue “Where do you want to install windows” appears, and create a single partition. While creating a single partition 3 other partitions will be created automatically with minimal storage space, which is mandatory for Windows:
https://www.howtogeek.com/197559/how-to-install-windows-10-on-your-pc/
Please download and keep all the device drivers from GPD. As you may need them after installation of windows.