DVDFab Decrypter should never take more than 20 minutes to rip a movie/DVD, if your system is taking more than that, then it's likely that you're having DMA issue. Try this DMA GUIDE to uninstall your drivers. Best of luck!!
It could be what alkohol said or it could also be that you have a scratch dvd and your dvd drive is having trouble reading it.
@travies06........ when a drive is having trouble reading a disk.... it can slip into PIO mode. that's a DMA issue. and follow Alkohol's guide! there should never be 10 hours to rip a DVD!