Acer V246HQLbi monitor: "No signal" problem

THE PROBLEM: despite having a working signal on both inputs (I've double-checked with other monitors/TVs) my Acer V246HQLbi monitor displays no picture with any of the input cable plugged in, it shows the "No signal" message and goes dark (into stand-by). When switched on, during the start-up the Acer logo splash screen doesn't appear (as far as I know/remember it should), the screen is lit (i.e. it's not completely dark), it lights up and shows the HDMI and VGA signs in the upper right corner consecutively and goes dark (into stand-by) after that. The whole OSD (On-Screen Display) menu cannot be brought up, just the (Select) "Input" part of the OSD menu (i.e. I can change input source from HDMI to VGA and back). As the OSD menu is not available, I could not navigate and use the "Factory Reset" option. The monitor detects the button are pushed, that's noticeable when changing the input source, as mentioned in the previous sentence.

SOLUTIONS I'VE TRIED:

1. switched off and then back on
2. switched off and unplugged and then plugged back and switched back on
3. based on some information available on the internet I've tried to switch off, unplug all cables, press and hold the "ON/OFF" button for 20-30 seconds (allegedly this is way of resetting the monitor)
4. also based on information from the internet, unplugging all cables and then plugging back the power cable while holding the "ON/OFF" button (waiting for it to blink 5 times)

To me it seems like a software/firmware problem or as if the the monitor would not initialize (boot up) properly when started, however this is just a wild guess.

Please, let me know if you recommend any solution working on the spot other than sending the monitor in for repair. I obviously would like to avoid the hassle of packaging, sending and waiting for it for a long time.

Thanks in advance for any informative feed back.