Question Thin horizontal lines. (HELP)

[CrystalDot]

Hello guys.
I have a weird problem:
I have 19 inch Samsung monitor

and this monitor has very thin horizontal lines , very hard to see, lines are on top or bottom of the monitor, but when i play games lines are almost everywhere.
Weird thing is that once i changed aspect ratio from Nvidia settings, lines gone from game. Everything was very clean.
So changing aspect ratio (which is adding black bars) helping me but i want to play full resolution without black bars. Videocard is not broken i'm sure for 100%, I tested on another Pcs.
If display is broken why does it helps when i change aspect ratio? I'm so confused.. I'm going to buy new display anyways, but i want to know what is going on here...
P.S sorry for my broken English.

 

[minesheep]

May be problem with your monitors video processor. Can you try any high bitrate video from another source? You can also carefully heat the back of the monitor with for example hair dryer, when inputting low bitrate video.