77L:
Row 22 is missing windows.
http://seatexpert.com/seatmap/11/Air...oeing_777-200/
77W:
Rows 19 and 22 are missing windows.
http://seatexpert.com/seatmap/12/Air...ing_777-300ER/
SeatExpert actually shows the relative position of the missing windows with respect to the seats! Pretty cool...