U3014, cannot access menu or turn off, #2

What is the solution for this problem? As I have the same one. My PC is turned off but monitor staying on with black screen and floating message "going into power save mode" and this stays for hours, until I switch manually the monitor. Sometimes there are artifacts and sometimes happens that monitor refuses to display the actually previously valid/set resolution in restarting system. I have to switch it off and then on to display the screen properly.