Very good - I forgot all about the tongue and groove. But today a different thought hit me - Why do we see all those nails ? I recall that tongue and groove
are nailed in such a way that the nail gets concealed by the next board. If all else fails then you have no choice but to nail from above...
I sanded a hardwood floor many years ago and it was great because the old floor was very bad and even though the power tools I rented occasionally misfired (left burn marks, and gouges) it seemed worthwhile in the end.
I didn't think of this at the time, but wouldn't it be possible to hammar...