mac screen has faint horizontal lines moving across it??

Hi!

Recently my Mac got these faint horizontal gray lines MOVING downwards across the entirety of the screen. I tried to calibrate the graphic settings but nothing helped them. The colors of these lines is very faint - they blend into the whitest part of the page but are still visible. Recently I also uninstalled a trojan virus that had been interfering with my computer so I'm wondering if that possibly had anything to do with it. I have a late 2010 11" Macbook Air.

Is there an easy way to remove these or is this something more complex (possibly caused by the trojan I recently removed?)

Thank you.