As discussed in the comments here are some suggestions to combat your problem:
- Use of a Bootable USB stick. You could use a Bootable USB with pre-prepared software in order to enter a "panic" mode which would Allow the use of USB Devices, or auto-matically re-configure the machine
- A time-sensitive PowerShell Script which will allow a time that USB devices are no longer blocked. Using Windows Task Scheduler you could have a script that could run @ 8pm to enable USB Devices and disable them again @ 9pm. This would give the client access to the machine 1 hour a day to fix or re-configure.
- Remote Access. You could use Windows Remote Desktop Connection to hook into the machine and reconfigure the device (We do it with the Intel Compute Sticks!). However this would require that you forwarded port 3389 from the router to the device AND you have a static IP (or Dynamic DNS) set up for that router. Failing this method, you could create a client/server script in Python which would give you some controls remotely without having to worry about port forwarding. There's a great tutorial for how this may work over @ thenewboston - Python Reverse Shell. The concept is to make the client machine contact the server over a TCP connection, server accepts the connection and then you can forward your system commands through to the client..