In the case that G-Data is installed, and Keyboard wont work on remote desktop connections ONTO the machine with G-Data installed:
Open RegEdit as Admin and find: “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GDKeyboard Guard”
Create “GDKBDisabled” as 32-bit DWORD and set it to 1
Reboot the Machine
This will most likely fix the issue.