Loading Windows onto a new computer is a relatively simple process. Determine what the boot sequence key is from your motherboard manual - usually it might be a function key or the delete key. Turn the computer on, and use the boot sequence key to access to boot menu where you can select the drive you are installing from a Windows disc or USB media. Follow the prompts on the screen to install, making sure to enter the product key when prompted. When choosing where to install, select the unallocated space - this usually is the only option to install Windows to. Once you have made these selections it will start the install of Windows. Once complete, you will get to a screen to create an account to access the computer. At that point, Windows is installed and ready for you to customize to your PC.