Not sure if the s7 has the same unfixed problem as the S7+... if so, you are now going to have a difficult booting into recovery, as that hard key option has not been fixed.
You can try power down unit... and then press/hold power+vol up to get to the menu that allows a factory wipe.
In that menu you can also try wiping cache partition (do this first).
If no luck getting into the menu, search this forum for S7+ reset....and you can find a thread where some users can access via plugging the unit into a computer and repeating the steps above.
Really would help if Samsung fixed this issue. Its been know for a while.
