Hello peterm6389,
I understand that your system is freezing during POST and you only get the POST code B9.
In regards to your problem, the POST code B9 is indeed for disabling removable media, this could be related to a device connected to your motherboard that is not being recognized properly.
I recommend you to test your motherboard on a basic configuration, only leave the minimal installed and try to boot the system up. When it boots, try adding one device at the time until you find the culprit.
Regards.