> brand new computer ... will no longer boot.
It's time to exercise the warranty that comes with a brand-new computer.
Scroll-down to the bottom of this web-page, to see the "About Us" hyperlink just above the "Careers" hyperlink.
Contact HP.
They may try to trouble-shoot over the telephone, or they may authorize you to ship the computer to a HP Authorized Repair Depot, for repair or replacement.