If an off-site server needs to be accessed via Remote Desktop Connection (RDC) client immediately, yet the Remote Desktop is not enabled on the server, it is a royal pain in the ass. Luckily it’s possible to remotely enable and turn of the Remote Desktop service on a remote PC or server by remotely editing its registry.

1. Login to the workstation with administrator credentials.
2. Run Registry Editor (regedit).
3. Click File
4. Select the Connect Network Registry in the pull down menu.
5. Enter the name of the required computer and press OK
6. A node for the remote computer network registry will be displayed in the Registry Editor with HKEY_LOCAL_MACHINE (HKLM) and HKEY_USERS (HKU) hives.
7. Navigate to the following registry key for the remote computer: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server
8. In the right pane, locate a REG_DWORD value named fDenyTSConnection. Double-click on fDenyTSConnection and change the value data from 1 (Remote Desktop disabled) to 0 (Remote Desktop enabled).
9. Reboot the remote machine by issuing the following command:  shutdown -m \\hostname -r