Does the device not read the DVD at all, or can you see the files on it but not play it as a movie? In the latter case, you have to install the proper software on your new system.
If, on the other hand, you are still running the old OS disk and / or the drive can't read data DVDs, it seems most likely that the drive is broken.
Can you read _any_ DVD now, either data or movie?
The new tower is my wife's tower which was working for her. Some dvd's work, others do not. On the dvd in question, when I look on the drive, there is nothing showing.