dvd shrink/nero sudden problem

i use dvd shrink and nero to back up my movies. occasionally i will back up a movie from one i already backed up (a copy). when i back up from a copy, it usually takes less than a quarter of the time than it does from the original. my problem is i have suddenly lost the ability to back up from a copy. when analyzing, it will get to 95 percent or so then an error message will come up. this happened one other time but before i could figure out what was wrong, i got a nasty virus and the entire computer had to be refigured. after getting it back, i reinstalled nero and dvd shrink and it has worked fine up to this point. if you can't tell, i'm pretty much a novice when it comes to computers. any help you could pass along would be appreciated.

Welcome to CD Freaks.

To backup a copy you should just be able to do a disc copy with Nero rather than run through Shrink again.

The problem you're getting might be down to the media degrading & so giving you read errors. If you've used Ritek G04 or G05 media then this is the very likely cause.

You could try backing it up to your HDD with DVD Decrypter as an ISO image. This app has better read error handling so might overcome the problem. A google search will find it for you and it's free.