Horizontal line on new Dell Inspiron N5040 screen

Hello,

I've just bought a Dell Inspiron N5040 laptop and after installing the Widows 7 operating system and all the necessary drivers I noticed that an orange line appears on and off on the screen when the image moves continously, i.e. when I have a window open and I close and open it continuously I can see the line always appearing in the same place. It is mostly visible on dark colours such as purple and blue. Another interesting thing is that the line appears only in the window I'm opening or closing and not on the whole screen and that it doesn't appear when watching movies. I ran the PSA diagnosis but there was no problem. What could it be and how can I fix it? Maybe there is someone out there who has experienced this problem and found a solution to it. I would greatly appreciate an answer.

Thank you!