Refresh/Reset/Clean Install on Win10 Activated Free Upgrade Version?

I have a 4 year old laptop that came with Win7/8 that I upgraded to Win10 (while it was free). The hard drive failed, so I replaced it, restored the OS to Win8 from backup, then upgraded back to Win10 and says it's activated.


I am planning to sell the laptop, but want it to be completely clean. It only has one User account which is a Local Account Administrator user. I guess I need to do a Win10 refresh or reset or clean install to get rid of all my User data... Not sure which one so that...

Refresh/Reset/Clean Install on Win10 Activated Free Upgrade Version?

Refresh/Reset/Clean Install on Win10 Activated Free Upgrade Version?