Just a fast check-up that'll strip the whole Windows thing and see if it is actually a driver problem, try creating a live Ubuntu USB and boot from it. Then try your Y key there. If it works, it's definitely Windows or the drivers. If not, the keyboard is bread.
Oops, I got distracted by something else while reading that part. Then how about removing EVERYTHING about the keyboard and let Windows load its generic driver? Remove all those gamer programs. Remove the keyboard from Device Manager as well. Try the key. Restart, try the key again.