External Monitor Problem With Precision M4500

I am having a problem when I connect my Precision M4500 laptop to an external monitor. Whenever I connect to an external monitor via the VGA cable I can see the laptop screen, but the image is almost unreadable because of strange horizontal lines. I have attached a picture to show the problem. This issue only shows up when I connect to my external monitor. The laptop LCD is fine and I have connected to my TV using a Displayport to HDMI adapter with no horizontal lines. I only have the problem using the VGA port. I have tried three different monitors and have the same issue on all three. The laptop does have a Quadro FX 880M video card. Is this a video card problem?