Scrolling diagonal lines on monitor

I don't think a picture would pick up the lines, they're very subtle and small. I don't think it has a refresh button.

This only happens in Mac -- I haven't seen this in Windows or Linux. I just don't want to be damaging my monitor.

I'll give that shot eMatoS. For me though, the lines appear only in Leopard, and start immediately on bootup, even if the machine has been off the whole night.

Nope, they're moving. They're scrolling very consistently, all in the same direction, but they're very dull. On my wallpaper, for example -- the lines exist only in the darker areas, and once I drag a different colored window over the region, the lines go away.

It would be helpful if you could take a picture?

If theres a refresh button on your monitor then that would be a good place to start.

Also, does this happen when your running windows as well?

After many hours working I've noticed thoes lines too, but not only on leopard also on windows. Solved it temporarely unpluging and replugging from the video card. (let it rest a while)