The only solution I have found to work until next time you shut down or reboot is to open the menu, go to Tool Icon and press and hold Reset button for a few seconds. You may have to do this several times before it "takes". Sometimes you may have to press Auto and Reset simultaneously. It is probably not due to your computer, or cables, or connection, video adapter, or board.

It seems the power adapter is failing on these might want to check yours

I fixed my monitor! I took it apart and pulled out the inverter board. I then removed the three capacitors on the board. Two 220uF25V and I believe a 47uF35V. Went to Radio shack and bought two new 220uF35V (I don't believe changing the max voltage made a difference.) and a 47uF35V Capacitors for $5 all together. Soldered them in and turned it on. Victory! It works again. It seems that this monitor is just made with cheap capacitors and they quit working. One note when replacing capacitors. Make sure you have the polarity right. It is marked on the board by a shaded in half of the capacitor outline and on the capacitor but a line on one side with negative symbols(-). I have seen capacitors installed wrong and they blow up, lol.