sounds like he/she has a corrupted upgrade... restore the 1511 image, then dl via MediaCreationTool and upgrade should have no issue that way
Just have fresh install windows 10 build 1067, then google and grab any Windows7,8,or 8.1 keys then open command promt as admin then enter slmgr -ipk <keys you grab from google>, then enter slmgr -ato. That is, Windows will activate.
Prolly now you'll really confuse him/her. MTK not needed. Do like Enthousiast hinted & Bat.1 posted. Change key from whatever whatever to teh one that starts with "3V7" and ends with "66T" Done. Must be connected to Internet when changing key.
Bat.1, your confusing me and maybe the starter of this thread, I thought we had to enter entire key, you say last 5, what's the deal, is MS entering the rest of key, Hmm, lol. What's he supposed to enter