Hi there
dont worry about the whole ATI thing, basically your motherboard has ATI Crossfire built in, AMD own ATI so its all wrapped up together
I think they are using the ATI moniker due to their driver system moving to the Catalyst system that ATI Graphics cards use, which would make sense when having drivers that do Crossfire/SLI functions.
Just let the install run it should be fine, however many people like to use driver cleaners and the like to clear out old versions before installing an updated driver.
Good luck