Elite X3 does not turn on

[MadameAAL]

the X3 turned off several hours ago, although the battery is fully charged and there is absolutely no way to turn it on.

This has happend several times already.

This morning was on and working perfectly and then it went off  on its own. I put it to charge and now battery is fully charged but still impossible to turn it on.

Any advice? 

the X3 is almost new, just have it for one month and a half. In perfect condition, never fell, never damanged.

[Domsci75]

I have a related problem insofar as following putting my Elite X3 into standby by closing the HP wallet case it often doesn't wake on opening. I have to soft reset, i.e., use [power] and [volume down] buttons simultaneously, to bring phone back to life. This is irritating but not a show stopper. However, it takes the shine off what otherwise is a seriously good phone, (in my opinion and for my usage)