I just recently bought a new monitor and I hooked it up and pretty much everything is fine. Every once in a while though the screen will get darker for about a half of a second or so. Is this normal for new monitors as I have not had a new monitor for a long time. It is a 21" CRT monitor if that helps anyone. When the screen gets darker for a short second it looks like someone has put a shade over it or something. Not sure if I have a messed up monitor or this is the way it is supposed to be. Thanks for your help. Have a nice day!!!