Power Button issue and Menu OSD doesn't come up

[NCH27]

I have HP 27es Monitor - Button layouts are: 1. Menu/OK 2. Info/- 3. Input/+ 4. Quickview/Auto Adjust/Exit 5. Power button.

Hey, so just got a problem of doing a power button unlock since it was locked somehow. After unlocking it, my menu now all of sudden doesn't show up. I may out of frustration pressed a bunch of the buttons to try to get it working it. (it reset to a brighter mode - want to change it to Low Light mode but Menu no longer comes up)

I've already did the whole factory reset by pulling the power for 30 sec and also overnight, plugged it all back in - pressed Power button - doesn't turn on.  Looked at the Manual and the web but with no success.

As previous posting, other buttons ASIDE from the power button can turn it on. (Long press Menu/OK button will turn it on- for whatever reason a short press of the Menu/OK button shows LED light for a second but does nothing)

Info/- button will turn it on. The Input/+ button will turn on as well.

The Quickview/Auto Adjust/Exit button will flicker between colors - Green - blue - yellow - purple - Cyan - White - Black Red and cycle. Shows that Power Button lock is on but if I leave it for a few seconds, it'll pop up saying the Power Button is Unlock without doing anything. I also have to unplug and plug it back in to avoid pressing this button again as I cannot do anything.

The weird thing is if I plug in the DisplayPort, it'll display. But my Power button doesn't Power on/off and I want to change the Default mode to Low Light Mode via the Menu but the Menu doesn't show up.

Please help.