Hello Adam_LT,
Thank you for posting on the HP Forums!
I understand the computer cannot detect the boot device. I will do what I can to assist you. Although the issue is hardware-related, there is some troubleshooting you can do. This troubleshooting is located in this HP document: Resolve Boot Device not Found Error Message
Hopefully this resolves the issue. If not, then the hardware would be deemed as faulty. Please contact HP phone support for assistance. You can utilize this website to learn how to contact HP appropriately, based on your region: Contact HP Worldwide
Please let me know if you have any other questions or concerns. Thanks for posting on the HP Forums. Have a great day!
Mario
