I use DVD-RW and +RW disks (brand names) for my backups. I use 3 disks and they rotated weekly. Today when I used one, the backup program told me that it was read-only. Ok, I figured that a disk had become corrupted or something, so I tried the other 2 with the same results. The files that I'm copying are definitely not read-only. My Sony DRU 510A burner and nero reports that it is still a burner that should be able to write, so what could be wrong? It has worked perfectly for several years. Should I use Nero to erase them all and start over. Thanks for any ideas. Ron N.