What do you do when you crush your chess opponent in 45/45 then he's like well now I'm not going to move and I still have an hour left?
Make note of who that person is and never play them again; they have very poor sportsmanship. In the meantime, go make a coffee. Relax. Read a book. Make sure they're not playing a surprise move, but don't give it to them. Also, you should complain to the admin about such behaviour. It is dishonorable and chess is a gentleman's sport.
If the clock runs out and both sides have sufficient on the board to win, the person who let the clock run out loses. If one side does NOT have sufficient on the board to win and the other guy lets his clock run out then it will be a draw. If one side does NOT have sufficient on the board and lets his clock run out, he loses. What he may do is try to offer a draw thinking you will fall for it.