I am trying to back up data daily for my wife's business computer. When using a CD, the process works fine. I tried to use a DVD -RW ( the DVD burner can use this format). The data backs up fine, but will not write any more data the next day. The disk is 'full' and not rewriteable. The setting for the job says that I can re-write over old data. Am I missing something obvious?. I thought to use the DVD so she can get more than a week of back up on one disk. Any suggestions? Same result with different burner programs. Thanks in advance for any help.