Hi, I am Dave, I will help you with this.
If you are booting your PC form a USB and you cannot see the drive to re-install Windows onto, do you have a modern Intel Processor on your PC
If you do, then you need to go to the support page for your PC on the manufacturers website, then from the chipset section, donwlaod the installer for the Intel RST drivers, then extract out the drivers form that installer into a new folder on your bootable USB.
Then when you cannot see the drive to install Windows onto, click 'Load Driver' and select one of the Intel RST drivers form that folder.