sounds like it is out of convergence. The red green and blue are out of alignment causing the coloured shadows. Depending on the model you can probably access the Convergence Menu through the Picture tab on the menu using your remote control. Many of the newer Philips offer a 35 point convergence for picture. If you have done this already then you probably have a much greater problem, but it depends on specific model, age, and what you have already done.
mark, November 2010