I use Windows Media Creation Tool to install a fresh Windows 10.  That way I can wipe out Dell's partitions (computers acted better) and get a more up-to-date Windows 10.  Then I use Macrium Reflect for backing up and restoration.

Step 1: Use your Product Key to download a Windows ISO off of the Microsoft website.

Step 2: Download Universal USB Installer. It will create a USB drive with the Windows ISO you downloaded in the previous step. This tool uses GRUB to do so.

Step 3. Plug the drive into the PC once creation in step 2 has finished. Power your Dell on and press F12 at the BIOS prompt. Select your USB drive to boot from, and follow the instructions to reinstall windows from there. 

You will be given the option to erase your drives, make sure all of your important data is backed up.