The Master Computer was a device in The New Adventures of He-Man.
The Master Computer was invented by the four Scientists of Primus, who worked on this project for Telks. It was housed in a special 'Master Computer Building' in the underground city of Onnor.
It's purpose was to connect all of Primus's machines, including the protective shield around the planet, into a single interlinking system. This would make life easier for the Primans, and allow Master Sebrian to finally take a vacation.
However, a disgruntled Priman hacker named Mikros, who had been exiled to the Mutant planet of Denebria had allied himself with Skeletor] who ordered him to upload a virus into the Master Computer. Mikros went one step further, by creating a computer creature he called the Argazoid to wreak havoc inside the MC.