Before we start, we'd like to share that we do not support people using a pirated or illegal version of Half-Life and or Non-Steam alike. If you don't have Steam and you either have a legal Half-Life CD-Key or you'd love to buy the Half-Life game in order to install Earth's Special Forces. Then please follow these instructions below. First, visit the steampowered website located at http://store.steampowered.com/, then download steam. Example image shown below: