CD-RW full disk can’t view contents

Windows XP. I had been saving my digital pictures to a CD-RW over the past couple of months. Everything was working fine, then I added a new folder to the CD-RW to prepare to add more digi pics and suddenly I can not add to or open the file on the disk! The machine reads there is no disk in the drive. I can not view the files in explorer or my computer, nor can I get the slideshow to work with it, which worked previously. Help! These are the only copies of the pics I have!