Windows 10: Laptop locks automatically and then goes off?

Hello,

For some time now, my laptop sometimes simply locks itself automatically with a blue lock screen and then automatically goes into sleep mode. I use Windows 10 64bit, have an intel Core i5 7200U and a Geforce 940MX.

:)

 

windows goes into hibernation and automatically starts

• After i install windows 10 creators update my Dell inspiron laptop begun to goes in to hibernation/sleep mode when plugged in. this doesn't happens when it goes from plugged in to battery.
  
• Also my laptop automatically starts (even in middle of the nights) and stuck in lock screen. because of this issue when i try to use my laptop, battery is almost drowned. laptop automatically starts even its plugged in.

Can you help me to resolve these issues.

 

laptop doesnt boot automatically

This is what happened.

1. Did a repair install and later disabled hibertnate in CMD.
2. Enabled legacy option ROM in BIOS.
3. After a few times startup ( i used the system in such mode for 5 days), changed boot option back to default.
4. Vola!! It boots automatically to win10 without any keypress. Tested it with many starts to confirm the same.
5. Re-enabled hibernate option using CMD and later selected Fast Startup.
6. System booted normally, without the need for any keypress.

I do not know exactly whether such steps resolved the problem or what else happened, hence cannot suggest above steps.

Many thanks to all members who helped to troubleshoot problems.

 

To ask why laptop locks automatically.

Actually my laptop is locked automatically when i was working . And i switched off my laptop and i am trying to open my laptop but it does's not giving me any response. Suggest me what what i have to do. As working on laptop is mine daily activity.