I use the Memorex 700mb, 80min CD-Rs. After I burn a cd, it will start to skip after a week or so, even if it has no scratches. I would like to know which cd-r is the best quality. I burn mp3s, and I make sure they are 128 or better. Even after I burn the cd with mp3s it will sound fine. But after a week it starts to skip, and there are no scratches on the cd. Please help. Thank you.