5x just turned off and now wont boot

[Darrenj1471]

Hello

I hope you can help me. This morning on commute to work nexus 5x just shut itself down. If I press and hold power button it will display the Google text for a few seconds and then nothing. (I have it connected to a charger too in case it was battery issue)

If I press and hold power and volume down I get to the troubleshooting menu but nothing seems to work. If I select Start I get Google text for a few seconds and then nothing.
If I select Restart Bootloader I get Google text for a few seconds and then nothing.
If I select Recovery Mode I get Google text for a few seconds more than before and then nothing and then the Google text comes back as if showing hope and then vanishes, then comes back for a 3rd incarnation ...and then nothing.

FYI the Secure boot says enabled but Device state says locked (not sure if relevant at all?) HELP as I don't know what else to try

Thanks

 

[Darrenj1471]

Update: Only thing which made any difference is selecting Power off from options in troubleshooting mode (power and volume down).
This seems to turn it off and then is displays the battery charging image. I then turn it on and it displays the Google text for a min and then REALLY quickly displays some yellow text saying something about Operating system but it was too quick to read and now I cant recreate

WTF is going on? Ive not changed anything.