To perform a clean installation of Windows, you will need a USB stick with a capacity of at least 8 GB. This USB stick will be used to create a bootable installation media, which you will use to install Windows on your computer.

Additionally, you will need a valid license key for the version of Windows you are installing. This can be either a Retail or OEM license key. You can buy a Windows license key from here.

Please note that performing a clean installation will erase all data on your hard drive, so be sure to back up and move any important files to an external drive or cloud storage before proceeding.