We should be more confident now to ask people to re-verify, re-install,
or try a different computer if it doesn't work out-of-the-box.

"Tails fails to start after the Boot Loader" and "the computer stops
responding" overlap but I don't think that it really matters here.
People in this section will be in "brute force" mode and try anything
that seems relevant.

'entirely' is a synonym of 'all'.

Except for the clone from Tails installation scenario, there is no
"first" or other USB stick.

- It will be useful for people search for this on our website.

- It makes it easier for Help desk to point to the relevant
  troubleshooting sections. (#14788)

- Thanks to the Shift+Restart technique on Windows, the Boot Menu key
  should only be used by Linux users now. Their computer should already
  have a minimum configuration to start on USB stick and they less
  likely need to edit their BIOS settings.