Although inserting and playing a DVD should be dead simple, a surprising number of things can go wrong. General error categories include problems involving the DVD disc and hardware (optical read errors), the software, the video playback, and the audio playback.
If you receive an error message such as “Unable to read drive X:” (substitute the logical letter for your DVD drive), chances are there is a physical problem with your disc or your DVD drive. Here are a few things to try before demanding a replacement from your video store or computer retailer: