while the movies and the books dont really match up, im sure i spotted a kid playing a handheld gaming device inside hogwarts in one of the movies...

as i understood it, computers and other technology could work fine, its just that the magic users didnt take the time to learn as magic was just as flexible, and available. why type search terms into google when you can walk into a library, speak some words and have all the books of interest drop down on your table in a instant?

two different means to the same end, pick one.

and if one really want to explore the tech/magic crossover, one should take a look at the backstory for a roleplaying game: mage: the ascension.