Says its a bad disc, but will play in another player. is the format the problem, if it is , how do i change it

That message can be generated in only 2 occasions:
1. the disk has been burned at a high speed and because of that the difference between the reflectivity of the data point and the disk background is smaller than what this player can detect so the player rejects it. The only thing you can do is to burn it at a slower speed.
2. the disk is coded in another format that your player can decode. Actually the only formats that this very basic player can decode are the dvd and vcd. If you get a disk in any other format you will have to load it in a pc, convert it to vcd or dvd and burn it again to a disk. For that you must install and use a converter, one like
http://www.softpedia.com/get/Multimedia/Video/Other-VIDEO-Tools/The-FilmMachine.shtml