If I leave laptop unattended screen goes black and won't respond until it's turned off and then on

[gdgraph]

My HP Envy 360 is about 2 years old and when I'm using it everything works great. It never overheats and the fan will come on and off when it needs to and it never just sits there running at full blast. If I don't use my laptop for 30 min to an hour, sometimes when I come back to it, the screen will be black but I'll hear the fan running and none of the keys or mouse will wake it up and I'll have to turn it off before I can turn it back on and then it'll start up fine. This has been happening for a few months now, and up until now, if I remember to manually put it to sleep this wouldn't happen, however now even if I do put it to sleep, sometimes when I come back to it hours latter the fan will be running and the screen will be black and I'll have to turn it of before I can turn it on an use it. Things I have done so far include opening the back cover and cleaning the dust with air (it was spotless clean and there was nothing to really clean). I tested the fan and it spun effortlessly. I also updated the Bios on the HP website. I also ran the HP PC Hardware Diagnostic Tools and every test came back saying everything was working fine.

[WAWood]

@gdgraph 

Win10 has enabled a new hibernation process known as Fast Startup -- which is enabled BY DEFAULT. This is different from Fast Boot, which is a BIOS/UEFI option.

Fast Startup is supposed to dramatically speed up the booting process, but in some PCs, it actually slows it down or causes it to hang. It's also a new form of hibernation known as hybrid sleep -- and this causes battery drain to maintain the state of the PC while turned off.

Disabling Fast Startup might fix booting and shutdown problems.

There are two ways to disable FastStartup in Win10: (1) through the Control Panel, and (2) through an elevated command prompt.

Control Panel - Open Control Panel --> Power Options.
Select "Choose what the power buttons do"
Select "Change settings that are currently unavailable"
At the bottom of the Window, under Shutdown settings, uncheck the box regarding fast startup

Elevated command prompt - run the following command:
REG ADD "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Power" /V HiberbootEnabled /T REG_dWORD /D 0 /F

In both cases, reboot Windows.

NOW, FastStartup is disabled.

See if that helps.

[gdgraph]

The fast power option box was already unchecked. Any other ideas on what I can do?

[WAWood]

@gdgraph 

Go into Settings --> System --> Power and Sleep and confirm that the screen shutdown is set to Never as well as the PC.

That should stop it going dark on you.

[gdgraph]

I don't want it to never go to sleep, if I leave it unattended for an hour I don't mind if it goes to sleep, the issue is that it won't wake up no matter what key I press or if I click the mouse.

The issue happened again only this time I know that I definitely put it to sleep manually and closed the lid. The next morning I came back and I heard the fan spinning and it wouldn't wake up again no matter what buttons I pushed. I had to hold the power button down to turn it off before I could turn it on again.