1. Try a clean boot and see if it changes anything - make sure to read instructions and make sure NOT to disable any microsoft services or windows won't load right -
https://support.microsoft.com/en-au/help/929135/how-to-perform-a-clean-boot-in-windows
if clean boot fixes it, it shows its likely a startup program. You should, over a number of startups. restart the programs you stopped to isolate the one that is to blame.
2. try this
right click start button
choose powershell (admin)
type
SFC /scannow and press enter
once its completed, copy/paste this command into same window:
Repair-WindowsImage -Online -RestoreHealth and press enter
SFC fixes system files, second command cleans image files, re run SFC if it failed...