Computers were first invented in 1946 and went on to achieve widespread commercial significance by the 1970s. So yes, computers existed in 1970.
Mainframe and integrated circuits that we now associate with modern PCs didn’t come out until the 70s and 80s. Prior to those times, mainframes were large machines best suited to organizations, such as banks or universities because they could only be serviced by trained engineers at the manufacturer or an authorized dealer. Early microcomputers like TRS-80, Apple II, and Commodore PET may look primitive as you compare them to today’s hardware; but they’re still “computers”