To unlock the OSD (onscreen display control), turn off the monitor and then press and hold the Menu button on the monitor. Then press the power button to turn the monitor back on. Do not release the Menu button before pressing the power button. This same step (holding the Menu button and then pressing the power button) enables the OSD lock. The menu button is the top button on the right side of the monitor (on the bezel). The power button is the bottom button of the group. AOC has the documentation for the 2036sa here: http://us.aoc.com/monitor_displays/2036sa
. See page 20 of the User's Guide for the OSD lock procedure. The picture of the monitor buttons is on page 19. The guide is available as a PDF on the AOC site. Note: you will need Adobe Reader or a similar program to read the file.
I hope this helps.