DVD reading problems

My DVD rewriter does not recognise a movie I am trying to play and record. It reports that there is no DVD present in the drive. Any ideas on what I should look for ?
Thanks for any help you may be able to give me.

Is this a commercial DVD?
What software are you using?
What’s the make and model number of your DVD drive?

[QUOTE=Dialysis1;2271489]Is this a commercial DVD?
What software are you using?
What’s the make and model number of your DVD drive?[/QUOTE]

Yes, it is a commercial DVD - I have tried 2 different movie dvd’s
My system runs XP Pro, and I have tried using DVDFab, DVD shrink,
DVD Decrypter, as well as ratDVD. I don’t know what make, but this is the designation given by the system ‘HL-DT-ST DVD±RW GSA-H21L’

I have tried 2 different movie dvd’s

Do [B]any[/B] DVDs read from this drive?
Have you tried cleaning the laser lens?