burn in

I have a mitsubishi 65 inch h.d. wide screen  projection tv, model # ws65315 . i really love it ,but you wouldnt know that concidering what i did. I left the aspect ratio 4:3 on for more than 15% of the time, now i have two transparent 4 inch lines from top to bottom on each side. i dont really notice them unless their is a bright background. I would like to eliminate the lines,it interfears with cinematic pictures. some one said it had somthing to do with the lamps. can this be fixed cost effectively and  would this be somthing i could do my self, such as replacing lamps. any constructive help would be greatly appreciated.