Does anyone out there know anything about LCD projectors? The one in one of the classrooms I use keeps turning itself off after about a half hour into movies. We've replaced the bulb, but it just keeps doing it. It also doesn't do that when I'm just showing PowerPoint presentations, and the other projectors don't do it at all, so I know there is something up with this one. It's just so frustrating to plan on watching a movie, only to have the projector shut itself off and refuse to turn back on.