During the past few months my monitor has shown evenly spaced vertical lines, a bit like Regency striped wallpaper. This shows mostclearly on a blue screen, where the stripes are a lighter blue, and on a white screen, where the stripes appear pale yellow. I assumed this would be either a graphics card or a monitor failure (I keep drivers up to date), but I have noticed that prints show a similar effect: a black and white photo I printed today has greenish-blue "Regency stripes", for example.
My setup includes the following:
Board: ASUSTeK Computer INC. P8Z68-V LX Rev X.0x
NVIDIA GeForce 8800 GTS [Display adapter]
LG L226W [Monitor]
Canon Inkjet iP4500 series
So the trouble obviously isn't with your monitor. But if anything you view has stripes and if you print them the prints too have those stripes? Then it sounds to me as though your PC data might be corrupted.
Thank you all for your comments. I printed one photo from the SD card via a USB stick. The stripes were still there, but much fainter. I also printed the web page I'm on now with the Print Screen function: this showed no problem.
I now suspect the graphics card. I think this does, or can, interact with the printer - perhaps I'm wrong. The trouble is that buying a new graphics card is an expensive way to find out...