Frequently Asked Questions
Question
What do I need to play Half-Life on line?
Answer
If you have no Valve games installed, you will need a Half-Life CD and a valid CD Key. Install the game.
If your version is earlier than 1.1.1.0, you will need to download and install the 1.1.1.0 patch
Next, you need to download and install Steam.
Steam will update your HL to version 1.1.2.0
Step by step instructions can be found here