Resetting PC won't work?

[Kirikoza]

I just got an old PC that used to belong to my friend and put a couple new parts in it. But since this was his, i'm still running his Windows 10, and I don't want that. Windows has an option to reset a PC; wipe all files from it and reinstall windows. But every time I try, it gives me an error message without telling me anything about what went wrong. I thought that maybe I could just get a Windows 10 installer on my USB, but that would require wiping this partition, which I don't want to do until I know what my product key is. I try to get the product key but all that shows up is what's in the picture. This PC was built by CyberPowerPC, so it wasn't installed by him directly. I have no idea where to find the product key. If any of you know where to find the product key or how to fix the error (which reads: There was a problem resetting your PC no changes were made) then please let me know.

Thanks!

[Slottr]

System builders usually do place the key sticker on the case somewhere.

[jj9987]

Windows 10 is activated so the key has been saved to the motherboard. You won't need any activation key during the installation.