Can you try another computer (or graphics card) with your monitor? This will
determine whether it's your monitor or card. If your monitor still causes
the same problem and if its not an electronic fault then it could be that
some device probably nearby is 'switching' causing a magnetic field to
interupt the display. I had a similar problem when I'd placed the power
supply adapter for my MSFF wheel behind the monitor when I was tidying up
and forgot I'd put it there.

Alan

"Franklin" wrote in message
...
My monitor's display seems to twitch slightly every ten minutes or
thereabouts.

It's just a very small movement but I notice it easily when I am
reading the screen. The movement seems to be mostly in the
horizontal plane. It never used to do this.

As best as one can guess, is this likely to be a fault with the
monitor or with the graphics card?

The monitor is a 17 inch CRT and the graphics card is an NVidia
GeForce2. Both are about 3 years old and have worked faultlessly up
to now.

My mains power supply seems fine. I recently removed several devices
from my PC (three hard drives) so PSU is more lightly loaded than it
has been.