You can control/ monitor one (or more) computers from a central one across a dot based network… the two best known ways are with vmware or hyper-v because these are complete systems but things like intel IPMI-view allow for easy internet access to a unRAID storage system.
Ipmi comes as a free download for people with compliant intel boards…
Vmware has more than one product depending on what level of control you want {i.e. systems or servers (perhaps running their own systems)}… vspear is their basic model for simple setups of single computers and still used on older networks.
Hyper-v is a very modern platform and handles everything from simple one-2-one interface up to clusters of servers… it’s still fairly new and currently comes both as an hidden extra in windows 8.1 pro or as a stand-alone server download from Microsoft… both are free.