Hi,
Don't pay money yet, first of all DVD-R are pretty chip and it is better to buy a new one then pay $50 on an old one which might not work again.
Second I had some problem with my CD-R and I asked in a free tech support. They gave me a solution that work for my problem (Updated the driver for xp).
Here is the page for
DVD burners troubleshooting support
I hope you'll find a solution
Marcella