Power Source

• Ensure that both the LG display and the device connected by the HDMI cable are powered on. Check the power cord on both, and if the connected device is a computer or laptop, make sure it is not asleep, restarting or hibernating.
  
  

HDMI Settings

• Make sure the television is set to "HDMI" or the name of your input. Look in the Control Panel of your computer or connected device to make sure the LG display is listed as connected. If not, disconnect the two and reconnect them. Connect the computer through a different HDMI port if possible.
  
  

Picture or Sound

• Go to your computer's Control Panel in the Start menu. In "Hardware and Sound," find the display settings and click "Connect to External Display." Uninstall and reinstall the display driver to correct any software malfunctions or issues. Find this under "Display Adapters" in the Device Manager if you cannot locate it in the Control Panel. Restart and reconnect your computer.