Some thoughts on computers in the classroom, based on my first three weeks as teaching assistant:
I have long hated flashing screensavers. They are totally unnecessary. All they do is provide a distraction for every eye in the room. Teaching in front of a row of monitors all merrily flashing and rotating a logo is like trying talk in front of a row of waving idiots. Teachers would not tolerate this behaviour from students, they should not tolerate it from computers.
Screensavers which activate in the middle of demonstrations cause the teacher to have to jump across the room to restore the display, and maybe even log in again. This is a completely unnecessary interruption to the flow of the lesson and a waste of time. For this to be happening 3 or 4 times in a lesson is totally unacceptable.
If a screensaver has to be used for security reasons then it should have a static display and the time before activation should be at least the length of a lesson.
When the students are working at the computers, it is difficult to get their attention away from the screen so you can address them as a group. There are nearly always some students who will keep surreptitiously clicking away, with one eye on the teacher and one on the screen. I did see one teacher demand that all his students switch off their monitors before he addressed them. This I think is a very good idea, and I will make a point of using it when I become a teacher.
The default screensaver on most computers in schools is, in effect, an unpaid advertisement for Microsoft. It would seem, therefore, doubly dubious that it is present in classrooms.