What is causing these colored horizontal lines on the monitor?

I just started having this problem this morning after watching a video on Youtube. But ever since, its not gone away at all! I have a Dell Inspiron Quad Core with AMD Processor. I made the mistake of having the graphics being on board instead of on a graphics card, does that mean I'll have to buy a new motherboard? Just wondering. I also have Windows 7 Professional. I tried to look in the Device Manager for display but it said it was working properly, obviously that's not the case!