So I have tha same problem with my 22'' monitor, but strangely when I resize or crop the Video in VLC to 16:9 those strange lines are gone...and it's not interlacing!!!
So the problem does not show up in WMP, meaning Koop is right, obey him!!
Short Version:
yesKoopiskeva wrote:its VLC, it sux, use MPC with the combined community codec pack instead.