HP Spectre 360-13 Laptop Screen Flicker

[AlanT123]

My wife has a HP Spectre x360-13 APxxxx laptop.  This morning she found that the screen was milky and flickery.  After a couple of hours of tedious searching I discovered the cause which was REALLY simple and since my searches didn't find the answer to our problem - just endless stuff about driver reinstalls, refresh rate issues, and even Windows re-installs(!!!) I thought it would be good to document the solution that we found on here. Hopefully it might save someone else some time and trouble IF they have the same silly issue.

The laptop has a function which changes the polarisation of the screen such that, unless you have it brighted up to the maximum AND you are looking at it head on, the screen will flicker and it will also look very milky (i.e lacking in definition).  This mode is, apparently, meant to prevent the person setting next to you on plane, train or public workspace seeing what is on your screen.  The problem is that, depending on your settings, this feature can be unknowingly activated by accidentally pressing F1 - and this appears to be what happened in the case I was dealing with.  Very easy to do that keypress without meaning to, on such a tight keyboard. 

Activating this mode is done by pressing the F1 key - and it just happens, there is no pop up to say "Screen guard activated" or anything useful like that!   Anyway, turning off this mode is equally easy - you press F1 again!!  Bizarrely, this setting (which is probably useless to a great many  owners of these laptops) seems to persist across reboots - which seems very ill thought out to me.

Preventing it from happening again takes a little bit more work.  What you need to do is set the laptop's BIOS to guard the special function keys with the FN key - i.e. rather than just pressing F1 to activate the display guard function, you would need to press FN and F1 together - which makes it much less easy to accidentally activate functions.  I believe that when the laptop is shipped the FN key requirement is activated, but if any BIOS reset or update has been done (often something that gets done during troubleshooting) then it gets turned off - again, bad design, guard ON should be its default.  

How do you get into the BIOS to change this? Shutdown the laptop.   When it is off put your finger on the ESC key and then with your other hand, press the power on button. After a couple of seconds release the ESC key.  This should get you to a menu on which you choose F10  BIOS.

 Once you are in the BIOS it's all faurly intuitive stuff, using the arrow keys to move around and the ENTER key to see lists of drop dowwn choices.

You will find the setting you need under "Configuration" and you step down to it with the arrow keys, press enter, select what you need and press ENTER again. Then press F10 and save settings and then the machine will reboot normally.  

Obviously there can be a  myriad of things go wrong with a laptop display - the display is the most vulnerable point on all mobile devices - but I  hope this may solve someone else's problem somewhere sometime.

I was frankly amazed that I could not find it documented anywhere here on HP support - or was I?