Most people at the Hogwarts School for Witchcraft and Wizardry are wizards, but not everyone there works as a wizard. The Setup Wizard is an example. He's not even a wizard. He's a muggle, but he can work magic with the local computer network.
On his blog, The Setup Wizard recounts his daily triumphs and struggles as he tries to keep the Hogwarts computer systems up-to-date and functional. You can read about his adventures here.