Monitor screen goes dim - why?

[sofasurfer]

Sometimes my LCD screen goes dim. This has happened periodically since I got the monitor. The image is still there but it is dim. When it does this the mouse and keyboard are non-functional. It stays like this for a few seconds to a minute or so. I thought this was at times when the system was overloaded. But it has also done it when I was doing nothing. It never happened with my old CRT monitor. I have replaced my motherboard and CPU since I got the monitor. So I think it is a function of the monitor.

Power supply, also replaced, is 500W.

Any ideas?

[electrogeist]

Are you using an application that stops responding, maximized to full screen? When apps get tied up the window dims. Does the panel/menu bar dim too?

I would say it is not a function of the monitor if it affects mouse and keyboard...the app causing very heavy cpu load maybe