Laptop closes down and sometimes won’t start first time.

[Sidco9]

Pavilion laptop shuts down unexpectedly. When I try to turn it back on it does not first time and seems to grumble for a second. Like a short Rev. 
I’ve done a few diagnostic checks and everything comes back fine. 
for the record I am using it now for last hour and it’s been working fine which it does from time to time so I was wondering why would it have these problems now and then. 
The lap top is my daughters and she uses it in bed a lot and I read static may cause these problems. The computer is just over 2 years old and apart from playing a game like Rodblox and sown streaming doesn’t really get vigorous useage. 
so to recap computer will sometime shut down and when you try to start it again it has a short whirling grumble like a short Rev then switches off again straight away with out starting but other times after leaving for few days works fine. 

[stevecomputer]

If it's a laptop kids leave it on the bed and it blocks the air vents and causes overheating which shuts down the laptop. 

[Sidco9]

No, we’ve stopped doing that. When it comes on it’s fine. No problem. But sometimes it won’t come on at all with the symptoms already discussed. I don’t think it’s a critical problem but something nots right. 

[stevecomputer]

Is anything plugged in to the device when it happens, like usb sticks or printers etc? Can you hear and unusual sound, like clicking or ticking? Dose the fan rev high? Does it happen when you start from the battery with no power in or when the  power is in?

[Sidco9]

It can happen with adapter or not. Like I say when it does come on it works fine. I’ve done all diagnostic checks and everything is in order. Although I’m struggling to do a Bios. I try to follow instructions but it never works for me.  

[Sidco9]

Ok just plugged in adapter and it’s come on first time of asking! It didn’t without it.