The Osd lock of the monitor shows how to handle it. First turn off the monitor, then press and hold the menu key, and finally turn on the power switch of the monitor (press and turn it on). You can press and hold [1] and the down arrow ▼ 10 seconds. At this time, press any key to display the locking information osd locking for 5 seconds. Then enter vga mode. If it doesn't appear again, it should be overclocked like this. Option 2: Desktop, Properties, Settings, Advanced, Monitor, adjust the refresh rate to 75. See if the problem has been solved. 3 Press and hold the menu key 10 second to see if it has been solved. 4 move the monitor to the balcony. On a sunny day, let the button face the light for a noon, and then see if it works. None of the above four methods is good, which proves that the control chip in your monitor is broken and needs to be repaired.