To access the service menu of an LG LED monitor and flip the screen, follow these steps:Turn off the monitor and disconnect all cables.Press and hold the "Menu" button on the monitor.While holding the "Menu" button, connect the power cable to the monitor.Release the "Menu" button once the monitor turns on.Navigate to the "Service" or "Factory" menu using the monitor buttons.Find the "Display Rotation" or "Screen Orientation" option and select "180 degrees" or "Upside Down."Save the changes and exit the service menu.Note: The exact steps and menu options may vary depending on the specific model of your LG LED monitor. Proceed with caution when accessing the service menu, as making changes to the factory settings can result in permanent damage to your monitor.