DELL S2440L 24" Monitor Flashing Black Lines HDMI Problem? With [VIDEO]

[pokerjk]

Hi,

I just bought the DELL S2440L 24" monitor but facing some issues.

If I got to max resolution 1920x1080 the screen has black lines flashing on it and every few minutes the screen goes black for a couple of seconds then comes back.

I found if I lower the resolution to 1280x720 there is no problem.

I am connecting via HDMI because my monitor only has VGA which my graphic card has only DVI which is a ATI Radeon HD 5700 series.

Here is the video http://www.youtube.com/watch?v=nh00hdEHo4c

Any help appreciated!