Greetings in that Divine and Most Precious Name of Lord and Savior Jesus Christ!
Was the Holy Spirit around in some form or other before Christ or was it new?
The Holy Spirit always existed with the Father and Son as far as our limited perspective is concerned. However, in the Old Testament, there was no universal indwelling of the Spirit, rather, God spoke and moved through selected Prophets and Patriarchs as He willed. The Holy Spirit moved through people in the Old Testament, including through "heathens" such as King Cyrus or even Pharaoh. However, after Pentecost, the Holy Spirit came to ALL baptised Christians. The Holy Spirit further indwells inside Christians who have been baptised and Christmated, even if they don't realize this or even abuse the privilege.
However, the Fathers of the Church have titled the Spirit "The Giver of Life" and so it can also be assumed that the Holy Spirit has always been a mechanism of the life force behind human beings since Adam, however the Holy Spirit didn't necessarily speak through everyone just because He blessed them with life, this gift of life to God was enough alone