I found these instructions:
1. Reboot, and repeatedly press F10 at the HP logo until the recovery screen appears.
2. When the recovery screen appears, press "Next" and then "Yes" to perform a non-destructive recovery (all data saved). After the recovery is finished, the laptop will reboot.
Or to perform a destructive recovery, (***This will erase all your unsaved data!***)
Click "Advanced" and then "Yes".
After the recovery is finished, the laptop will reboot.
Reboot, and repeatedly press F11. Follow on screen prompts.