Screen Flickering with certain images...

Hey there, I have an HP HDX18T with Windows 7 64-bit. Recently, when I am on certain web pages, or have certain wallpapers/backgrounds applied, my screen starts flickering between a lighter and darker shade. It usually happens when the image has both vivid and dark colors (such as a black border around a lighter image. To make matters worse, when this happens on certain web pages, the screen will not only start flickering between light and darker shades, but sometimes will start flickering black in certain spots at a very quick rate. I'm not sure whats happening, but I did just get a low primary battery warning before start-up. The laptop's only a year and couple months old. Thanks.