Going back to Windows 7 depends on how Windows 10 was installed. The built-in Go back option is available only for a limited period after an eligible upgrade and needs the old installation files.

Before rollback or reinstall, save an image of the current Windows installation to another physical drive. This gives you a route back if Windows 7 fails to install or lacks drivers.
Step 1. Connect an external HDD or SSD with enough free space, then open Backup and Recovery > System backup.

Step 2. Review the selected Windows, boot, and recovery partitions. Confirm that the system shown is the one you want to protect.

Step 3. Choose the external drive as the destination. Confirm its free space and task name before starting; avoid the same physical disk that holds Windows.

Step 4. Click Proceed. Wait for the progress screen to complete and check the image at the destination. Keep bootable recovery media separately.

The rollback files may have been removed, the time window may have expired, or Windows 10 may have been installed cleanly. A Windows 7 system image made before upgrading can restore the old system, but restoring it replaces the current Windows installation. Otherwise you need licensed Windows 7 media and a clean install; programs must be reinstalled.
Windows 7 no longer receives ordinary security updates. New hardware may lack Windows 7 drivers or boot support, so check compatibility before erasing Windows 10.
Can I use Go back after a clean install? No. Without the previous Windows installation and its rollback files, use a saved image or installation media.
Will rollback keep newer apps? Apps installed after the upgrade may need to be reinstalled.
Use the built-in rollback only when it is genuinely available. Otherwise plan a verified image restore or a licensed Windows 7 installation, and weigh the security and driver limits before switching.