Hi,
Thanks for posting your query to Microsoft forum. I will certainly help you with this.
Are you able to boot to Windows 10?
You can get an Installation Disk created from the link below:
https://www.microsoft.com/en-in/software-download/home
Now initiate custom installation of Windows 7: Installing and reinstalling Windows
There are two options to choose from during the Windows 7 installation process:
• Upgrade. This option replaces your current version of Windows with Windows 7, and keeps your files, settings, and programs in place on your computer.
• Custom. This option replaces your current version of Windows with Windows 7, but doesn't preserve your files, settings, and programs. It's sometimes referred to as a clean installation for that reason.
You can back up files to an external hard disk, a DVD or CD, or a network folder. We recommend using Windows Easy Transfer to back up your files and settings.
Let us know if you need further assistance. We will be glad to help you further.
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Thanks & Regards,
Isha Soni