A CD/DVD drive may not work for a variety of reasons. One such reason is the presence of dirt, dust, and other debris on the disc, which prevents it from spinning or affects its speed. A CD/DVD drive might also produce errors if it was last used with a copy-protected disc and there is now no readable data: When trying to read an original protected disc, most drives produce an error message, such as Windows Media Player cannot play the file because the format or code has been changed. Further causes for an unreadable CD can be scratches or water damage to the disc. The laser reader head inside the optical drive could also be dirty due to handling dusty CDs and DVDs.