Dreamcast won't play burnt games anymore

Ok, get this... 3 months ago I burnt three dreamcast titles and they worked perfect, and still do.. Well today I burnt 5 more games, and they worked perfect in my friends dreamcast, but mine won't even read them.. It just carries me to that dreamcast boot up screen and acts like its playing an audio CD.. I know I burnt the games right because they work fine in my friends console.. Anyone have any suggestions why they won't work in mine?