Summarize this article in one sentence.
It’s usually at the bottom-left corner of the screen.  The computer will power off and back on. Instead of booting to the desktop, you’ll see a blue menu titled “Choose an option.”   You are now at the Windows boot (Startup Settings) menu.

Summary:
Click the  button. Click . Press ⇧ Shift as you click Restart. Click Troubleshoot. Click Advanced Options. Click Startup Settings.