HP ProDesk 600 G3 Maintenance And Service Manual page 110

System will not boot from USB flash drive.
Cause
Boot order is not correct.
Removable Media Boot is disabled in the Computer Setup utility.
The computer boots to DOS after making a bootable flash drive.
Cause
Flash drive is bootable.
Flash drive is defective.
102 Chapter 6 Troubleshooting without diagnostics
Solution
Run the Computer Setup utility and change boot sequence in
Advanced > Boot Options.
Run the Computer Setup utility and enable booting to removable
media in Advanced > Boot Options. Ensure USB is enabled in
Storage > Boot Order.
Solution
Install the flash drive only after the operating system boots.
Try a different flash drive.