"You have a legacy CD Key assigned to your Registry account.
You were issued a Steam CD Key before the automated process was put into place. Your Registry and Steam accounts were linked, but your Registry account was not upgraded.
To upgrade your Steam account, you will need to manually activate your key on Steam. For reference, your key is listed below. "
This is what it said. I did activate it on steam and I am now playing it using steam. What I can't wrap my head around is why does my friend have an upgraded registry and I don't, seeing as how we bought the game the same day to play it together.