If you're gonna completely factory reset the Toshiba Laptop where you want to delete your files and everything then you'll need a new operating system disk and your license key for Windows 10.
You can purchase a Windows 10 operating system disc online through Ebay or create your own bootable USB drive with Windows 10 on it or a DVD of the Windows 10 operating system and then reinstall the operating system completely.
Reinstalling the operating system of Windows 10 will completely delete all files you had on your computers hard drive so be sure to backup any important data before reinstalling the operating system.
When you reinstall the operating system on your Toshiba Laptop it will be like a new computer.
Then you just need to enter your windows 10 license key after installing Windows 10.