Not much you can do if it is true burn in... No more 4:3 for you.. use the zoom or the fill for now on.

You will have too run the break in disc for like 1 month stright & MAYBE it will help depening on how bad it is.
Here you can get the 'break in DVD' to burn to a DVDr/rw, it is FREE (you have to unzip before burning):