Thanks guysI found you machine here:
Looking for upgrade or update information? Trying to find the names of components or programs? This document contains the technical details for this product.support.hp.com
Shame it doesn't tell me what BIOS you have.
1. Try following the instructions that poorguy posted for you.
2.If that fails I would give HP a call and get a rep to help you get into the BIOS and disable the secure boot.