Nostalrius Begins - Quality wow vanilla realm (1.12)

Can I still register to enter the game? If so, how and where? thanks))

You can only create two accounts per IP, so you need to create the account from either another computer or simply your smart phone.

This does not effect your playing; this is not limited to two clients per account. However, you can of cause only play one account at a time (multiboxing is not allowed).