My monitor's picture twitches every now and then. It's a little twitch. I know that electronic devices can do that like when my television is turned on. I don't if my picture twitches because some electronic device is turned on in my house. Can my uninterrupted power supply be the problem? And can anyone tell me that if something is wrong with my monitor it always stays wrong like that and just doesn't "click" in every now and then? I have a NEC Multisync FE770 monitor(CRT).

How old is your monitor?

Sometimes, picture tubes just go bad... I've got a screen myself that behaves similarly. About the only thing you can do to "fix it" is to buy a new monitor.