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.