Fox plans this Fall to sell full-length movies and TV shows online that will only be compatible with Microsoft Windows Media Player. At launch in October, movies will include “X-Men: The Last Stand,” “Garfield: A Tail of Two Kitties,” “The Omen” and “Thank You for Smoking.” TV offerings such as Fox’s “24” and “Prison Break” and FX’s “It’s Always Sunny in Philadelphia” will also be offered, with new episodes being made available within 24 hours of broadcast. Movies will sell for about $20 and TV shows for $1.99 an episode. Fox will use a platform called Direct2Drive, currently used to sell video games, for controlling the download and playback of the content. The movies and TV shows will be limited to playback on two Windows computers, each supporting one portable device.