LOL, I should've guessed. DRM is Digital Rights Management, a means of protecting digital audio/video content with a "license" In simple words, the author of the content will protect the file with a DRM license, and to be able to play it, you will need to download and install the license from the site that you downloaded it from. Mostly these are protected content that require you to pay for them before you can download the license, install it and play the content. The best thing to do is to upgrade Windows Media Player to v10 if you're using Windows XP. If not, go ahead and download the additional DRM components required. That should automatically solve the problem, because when it detects protected content it will automatically try to acquire a license for it, if that option is enabled.