Ok, here is the info from the Tech attempting to get this working. Please let us know if you need any further info. Again, thank you for your help.
"We are booting to a USB utility, known as AOMEI Backupper, using WinPE. However, it is all USB utilities that fail - But these utilities work fine on all other HP models with different BIOS'.
The USB drive is formatted with NTFS.
These HP EliteDesk 800 G2's originally came with Windows 10, and we are loading them with Windows 7.
Yes, the USB ports all work fine under Windows 10 and Windows 7. In fact, the USB ports are live, and function as designed, until about halfway through the boot up process of the USB WinPE utility. At about the point where the four Windows colors converge (within the WinPE boot up) is when the USB ports all shut off."