Who created the Holy Spirit? Did the Holy Spirit exist from the beginning or was it God who created the Holy Spirit? If it was God, then why is it said that the members of the Holy Trinity is independent of each other but form an eternal Triune God?
According to mainstream Christianity, the Holy Spirit is a person of the Trinity - loosely speaking a part of God. Therefore he was not created. He is eternal, without beginning and without end. This is best (though not necessarily most understandably) summed up in the Athenasian Creed:
Something around 98% of Christians adhere to this view.
For those that do not believe in the Trinity, the Holy Spirit is usually considered to be an 'impersonal force', or the action of God, or simply another way of referring to God (as opposed to a separate person). In these cases there is also no question of "who created the Holy Spirit". He has always existed.
According to the theory of the trinity, the holy spirit was never created as the theory holds that the holy spirit is god just as the father is god and the son is god. Since the trinity theory promotes that the father and the son are from eternity, so then is the holy spirit also uncreated.
According to scripture, the Holy Spirit is uncreated as the Holy Spirit is the operational presence and power of Yahuweh (God), but is not a seperate person from Yahuweh (God) Himself. Though not being a seperate person, the Holy Spirit is still "personal" just not a "person".