I have a Toshiba L500 Notebook, which I have had for about 2.5 months and I have RECENTLY been having trouble with my DVD disk drive. It will read some disks but not all. It is mostly alright with CDs but is worse with DVDs. It will read MUSIC CDs and CDs with files saved onto them and it will burn CDs, but it would not play a CD that had had music burnt onto it. It registered the disk, but not the files on it. It said that the disk was blank and asked me if I would like to burn files onto it (which I didn't try because there is already files on it that work FINE).
I have had a lot more trouble with DVDs. I have tried to play several DVDs (some of which have played fine before) but it has only played one, which was a cheap movie (so it might not have the same protection/quality!!) When I put a DVD into the disk drive it starts making loading noises, but they get quite load and it vibrates, a bit like when you put a scratched disk in, but worse. Then it dies down and some start making a scratching type NOISE, (a bit like you make in the back of your throat) but it doesn't damage the disk. When the disk has finished ‘loading’ and you go into ‘my computer’ it says that there is no disk in the disk drive.
I did download SecuROM Diagnostic Tool so that I could play an EA Game and I’m not sure if that would have done anything, but I’m sure everything has been working fine after that anyway.
Maybe try to clean the laser inside the optical drive with a little bit of spirit on a cloth.

You bought this only 2.5 months ago so its still on warranty so the best WAY is to go to the shop and let them do it. If you decide to clean the laser your self remember that your warranty will expire once you take out the DVD-DriveTake it back to where you bought it with a few of the DVD's that won't play to demonstrate for them. Get it replaced.

Alan <><