All of a sudden the Windows Start Button turns brown (not blue) and when I left click on it something is said about having to sign out and a critical error. Clicking that button, which you have to do to get rid of the dialogue box, restarts the OS and it happens again if you left click the Start Button.

Also, Microsoft Edge, which used to be on the bottom row, is now gone.

I tried to reinstall Windows 10, but got to a point where the setup crashed, so I am stuck.

Any help would be greatly appreciated.