Not easy but bare with me:
Connect a keyboard to the USB2 ports, connect a monitor to the vga port.
Boot the unit up, after (exactly) 60 seconds you will be presented with 4 options:
1.RAMroot 2? sda1 3......
As soon as you see these option press 1 and enter on the keyboard and let the unit boot, after a couple of minutes you should see the screen go red and the Nas Navigator will say it is in EM Mode.
Once it is in this state, download the latest firmware (2.42 i think), unzip the firmware and disable any AV and firewall software.
Right click the TSupdater.ini file -> Edit and it will open notepad.
Noformatting=1 (change the 1 to 0)
Debug=1 (Change the 1 to 0)
Exit and save the file.
Open the TSupdater.exe file -> Right click the title bar -> Debug.
On the right hand side tick "force update" and "delete user data partition" (the latter option doesnt touch the data but resets the admin password.
Click OK -> Update and proceed with the update as normal.
Let me know if it works.