Mac Cds No Icon


My G5 has OSx. I am trying to use discs that I have used before and the computer will not show the icon. Like It can't read it
I've zapped the PRam, made sure my box for CD, DVDs was check. I then used disk utilities and repaired permissions. when I put in the disk while the program was up I could see but it would not mount an icon on the desktop. Any suggestions. this all started after I burned a CD.