Disabling Remote Desktop connection can be very easy and depends on the way you want to do it. You can either use the standard feature you can find in desktop mode like Start > Right click on My Computer > Properties > Remote > Uncheck both settings you find on that page or use regedit to manually disable the feature by using Start > Run > type regedit and press Enter.
Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server then double click fDenyTSConnections and set the value to 1 in order to disable the feature. A reboot is required for the settings to take effect.