Download installation media from Microsoft, install either by usb (need at least 8GB) or dvd (burn a blank dvd).  Press F12 to choose to boot from usb vs dvd At beginning of install choose the edition in menu consistent with Win 7. i.e., if you have Win 7 home, choose Win 10 home during install. Do not type in Win 7 key at beginning of install. Rather, activate Win 10 after install is completed using Win 7 key.
I intend to reinstall Windows to my XPS 8300 and I have the below questions: 1. What shall I do step by step? 2. Shall I make a backup using CD or USB before formatting the hard drive? 3. The license was Windows 7 but now has already been upgraded to Windows 10 Home. Will there be any licensing issues? I have the product key for Windows 7.
XPS 8300, steps to reinstall Windows