Well one option would be to use the Windows 10 Download tool to make a bootable USB which should accept your Windows 7 (non enterprise) serial number to allow you to do a fresh install of Windows 10.
Most PCs and laptops have a recovery partition. If it is still there, changes are good if you only formatted the C drive, you may be able to start a recovery to factory setting by using some control-key during start up. Look in the (on-line) manual.