The monitor is about two years old and is a CRT. I have been using it without any problems since I got it. Something else of relevance - I took a screen dump last time it happened and the problem shows up on that. I guess that says something about where in the pipeline the problem is.

When I say that my desktop resolution does not change I mean that as far as windows is concerned, it hasn't changed; obviously in reality it has. I am not sure exactly what you mean by system monitor settings - do you mean the device manager in the control panel? That will be very hard to check out when the error strikes but I'll try!

Cheers for your help.
Ross