Many keys found online are blacklisted or intended for specific OEM hardware versions, meaning they won't work on a standard installation. How to Get a Legitimate Key
Are you trying to get a specific working, or are you just looking for a general media player to handle old files?
A powerful tool for digital TV that has a free version capable of handling most basic viewing and recording needs.
Visit the website of the company that made your TV tuner (e.g., MyGica, August, or KWorld). Many provide a "driver and software" pack for their specific devices that includes a licensed version of TotalMedia.