In Russian we have a word эникейщик [eni-kay-schick], literally "any key person".
This is someone whose job is performing very basic, routine computer-related tasks: install a driver, set up Internet access, connect a printer etc.
This is not a system administrator: the system administrator does more complex tasks, like desiging and implementing security policies, setting up backup and restore plans, and so on.
This is a somewhat derogatory term, assuming the person is not able or not willing to do something better than this.
What do I call a person like this in English?
"Do you guys have a system administrator?"
"No, we're a small company. We have a _____ who comes and fixes our computers for 20 bucks and a pizza".