Enabling Remote Desktop on Remote Computer using Registry

1. Start Registry editor. regedit.exe
2. Connect to remote computer's registry. ( File--> Connect Network registry...)
3. Select remote computer registry on tree
4. Navigate to
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
     
Double-click fDenyTSConnections.

Change value to 0 for Enable
Change value to 1 for Disable