I have an HP 250 G1 laptop that came loaded with Windows 8. I later installed Windows 7 in Legacy mode. Now I want to go back to Windows 8 in UEFI mode. I just want a clean untouched Windows 8.1 .iso that will preferably use the key already in this laptop. Thing is I had Windows 8 on here before, not 8.1. I don't know if my key can still be used. Can anyone provide a link?