DVD/CD won't show files

I have used CCleaner for more than a year. I noticed today that it erased part of my Sent file (2006 onwards) in Outlook Express when fixing registry. I had kept a backup so fortunately I was able to recover the file.

That made me think that CCleaner did something to myCD-DVD drive. I backup my folders once a month If I download numerous folders (I use Roxio CD Creator), only one shows in Windows Explorer. Yet the CD-R disk shows that all have been written. If I take this disk to a different computer, all folders show up in Windows explorer. I went back to my backups and found this the case going back to July 2007. Unfortunately I had deleated my backups going back that far. Why can't I read the folders on my drive? Could it have been CCleaner? Any solutions?