Windows 11 on second PC

Hey guys sorry if this is the wrong group please refer to the correct one if so.

In short I just built my system and giving my old system to my GF. I reset the whole thing and wiped it all. I’m seeing if I can use my copy of windows 11 and install it on hers using my old windows 8 key or not. Or if there’s any other tricks ? TIA

Edit: since I wiped it it’s trying to use my old sign in but when passwords typed in gives an error of profserv or profsys (can’t remember) so wanting to see if I can use my windows 11