Is the hadd punishment for theft, involving the cutting off of the hand, obligatory for someone who has downloaded free games and movies from the internet instead of buying them, and how can the rights be returned to their owners if they cannot be remembered?

Downloading protected programs and games without the owners' permission is an infringement on intellectual property rights, and not a theft that necessitates the ḥadd punishment of cutting. Whoever does this should strive to contact the owners of these programs and games to seek their forgiveness or to compensate them. If that is not possible, or if the rights holders are forgotten, then one should give charity on their behalf to the best of their ability. Al-Ghazali said in "Minhaj al-Abidin" that repentance from financial sins involves returning the money if possible; if unable, then by seeking forgiveness; and if the owner of the right is absent or has died, then by giving charity on their behalf.