CSS encrypted DVDs wont read in drive

I have a Sony VAIO PCG-GRT716S and have been using it happily for the last 2 years. The last couple days I have not been able to get some (store brought) DVDs to run in the drive. It is reading CD's fine and a couple DVDs, but wont play SIN CITY. One time I finally got the DVD reading, but as soon as I tried to open up a program to play it in, it just crashed. I got the following error message from Windows Media Player:
"Windows Media Player cannot play the DVD because a problem occurred while configuring copyright protection"
I also got another error message saying it was due to a CSS encryption problem. I am pretty sure I have played CSS encrypted DVDs before.
I don't know what to do since the DVDs I am running are not fake and others play. Does anyone know what the problem could be? I would think it was the drive but it since it still reads cds and other dvds then I have no idea.
Any ideas on how to fix this or what the problem could be?

So what you're saying is you pop in the CD, and you can't even play the movie at all?

A bunch of the newer DVDs have CSS encryption. See if you can find out if any of your other current DVDs have CSS encryption and try playing that movie just to see if it might be the Sin City DVD that is malfunctioning.

Also, try updating your DVD-RW drivers.

If you're trying to copy the movie for backup purposes, I've heard of people that have had success using AnyDVD and CloneDVD2.

Good luck.