Enable remote desktop on remote Windows 7 computer

There is a Windows 7 computer that is a member of a Server 2012 R2 domain that is locked up in a closet no one has access to that I need to be able to remote desktop into.

Past administrators have been able to logon to this computer using the domain admin account as well as a local administrator account on this computer.

However we are unable to remote desktop into this computer since it doesn't have remote desktop enabled.

Is there any way of enabling remote desktop on this Windows 7 computer so we can remote desktop into it from the Server 2012 R2 server?

Please provide me with the steps on how to do this.