I use old tube tv's for computer monitors in the arcade machines I build that run off PC's. one doubles as my main shop computer and music machine. the main difference is the resolution. even with a good tv-out card, the graphics are not even close to a tube monitor, or newer LCD monitor. that said, no reason you can't use one, i've been doing it since '02. I use the S-video out for the best resolution on the old tubes.