Video & Audio choppy on DVD-ROM drive



I was getting “Internal Error. Cannot build graph” error when trying to play DVDs using Nero Showtime 2 (Nero Express 6 suite) on my SONY laptop’s built-in DVD ROM drive. So I changed Hardware acceleration to low under Display-> Settings-> Advanced and then managed to get rid of this “Internal Error” message and got the DVDs to play. But now the problem is that the video & audio from DVDs’ is choppy and they appear in frames.
However I have no problem when playing CDs’ on the same drive.
I connected a Memorex 510L V1 external DVD burner to my laptop and faced the exact same behaviour when playing DVDs’ while audio CDs’ played fine. So this confirms that it has to be something with my laptop ?
Any inputs on why this is happening and how it could be resolved would be helpful.