My laptop refuses to turn off

[Kubaz2308]

Hello everyone
I have Lenovo Y700 (80RU002YPB) with:
Intel i7-6700HQ
Intel HD530
GTX 950M 4GB (removed)
8GB 2133 MHz RAM 
120GB SSD + 1TB HDD

So as you can see my GTX is removed. Few weeks ago whenever I tried turning the computer on with "Discrete" selected as my graphic device in BIOS,  I was getting BSOD with VIDEO_SCHEDULER_INTERNAL_ERROR code. Because I have no required tools and not much experience in fixing laptops, I gave it to a service in my city. First they confirmed that GPU chip is dead. Then they replaced it with a new one, but they said that system was not detecting it. They thought it was faulty and ordered a new one, but it was not detected either. They gave up and gave it back to me. The same day I took it from them I turned my computer on and looked for something on the disk, then I turned it off and it was fine. A bit later the same day I turned it on, then turned it off and it was fine. But in the evening that same day, when I came back home, I plugged in the charger, my mouse and keyboard, microphone and speakers. I watched some youtube videos, then turned it off and... it didn't turn off. Mouse and external keyboard backlighting were off, but laptop keyboard backlight was lighted and the screen was completely black (like when turned off). Pressing any buttons didn't give any effect and in order to turn it off, I had to hold down power button for few seconds. Next day I tried to fix it. Unplugging everything - didn't help, updating system - didn't help, removing recent updates - didn't help. I ran DxDiag, there's a BSoD from yesterday (06/27/2020) but I didn't see any BSoDs in last week. So I turned it on, used it a moment, turned it off and ran DxDiag again. Most recent BSoD didn't change, its still from yesterday.
What can cause this problem? I could try installing fresh windows, but I don't think that will help... So I'm waiting for some help... Maybe this time fixing one thing won't result in something else broken... Any ideas?  

[WaterSheep]

laptops that refuses to shutdown sometimes can be fixed by resetting your power option, however i doubt that's the main reason..
have you got a glimpse on what error BSOD showed?
or try to look it up in your event viewer