Power-off your computer. Power-on your computer, and look for a message like "Press <blah> to enter BIOS SETUP". Press that key. Somewhere within BIOS SETUP should be an option to automatically start when the power is restored.
Be alert for scammers posting fake support phone numbers and/or email addresses on the community. If you think you have received a fake HP Support message, please report it to us by clicking on "Flag Post".