Hi,
My name is Todd and I'm with Dell's online outreach program. When you say it won't play a DVD are you referring to a movie, or a DVD with data or software on it? If it's a movie, what happens when you try to play it? What software are you using to watch it?
If you've already changed out the drive it's most likely a software problem and depending on what is happening there are a couple ways we can try to get it working correctly. If you can give us a bit more info we'll see what we can do.
Thank you,
Todd
Customer Advocate
Dell, Inc.
Direct2Dell - Dell's Blog