Welcome to the Forum.
I donâ€™t want to disagree with a â€˜Retired Moderatorâ€™ but doubt you problem has anything to do with your PlayBack/Viewing Software program but lies with the particular Commercial DVD Movie Title you are attempting to view.
Some Commercial DVD Movie Titles have very overly aggressive anti copy protection schemes that make playback viewing almost impossible. This has nothing to do with your Optiarc AT-7170A Optical Drive or your playback viewing software program. It has to do with the overly aggressive anti copy protection schemes employed in the particular Commercial DVD Movie Title. I have had to personally take back numerous rented Block Buster Commercial DVD Movie Titles until I could find a copy that would correctly play in my Home Theater System. I can assure you that it is not my Home Theater System that is at fault â€“ the problem is that these Commercial DVD Movie manufactures are employing very overly aggressive anti copy protection schemes and because of this are manufacturing DVD Movies that do not meet the â€˜DVDâ€™ technical standard specifications which causes Playback Viewing problems.
The remedy to your problem is not to purchase a new Optical Drive but is to return the offending Commercial DVD Movie Title and demand a copy that was correctly manufactured.