Enable Remote Desktop Remotely with PSEXEC

Download PSTOOLS from microsoft. Unzip to an easy to access location.
Open a CMD command prompt, navigate to the PSTOOLS location.
Execute:

psexec \\machinename reg add "hklm\system\currentcontrolset\control\terminal server" /f /v fDenyTSConnections /t REG_DWORD /d 0

Machinename should be replaced with the computername, ideally you already have admin rights to this PC, for example you run this as the domain administrator. Otherwise the have to supply credentials using -u and -p options.
If you still can’t connect this is most likely the windows firewall.
Execute:
psexec \\machinename netsh firewall set service remotedesktop enable
psexec \\machinename netsh firewall set service remoteadmin enable