If you don't already own L4D then you should definately go and purchase it now from Steam.
It's 75% OFF!!!!!!!!

System Requirements
Minimum:

Supported OS: Microsoft Windows XP / Vista / Vista64
Processor: Pentium 4 3.0GHz
Memory: 1 GB
Graphics: 128 MB, Shader model 2.0, ATI 9600, NVidia 6600 or better
Hard Drive: At least 7.5 GB of free space
Sound Card: DirectX 9.0c compatible sound card
Recommended:

Supported OS: Microsoft Windows XP / Vista / Vista64
Processor: Intel core 2 duo 2.4GHz
Memory: 1 GB
Graphics: Shader model 3.0, NVidia 7600, ATI X1600 or better





- The Problem Solver

Featuring the all-new ‘Level Up’ Content Pack that includes 3 Maps, 7 Weapons, 20+ Steam Achievements and More! Plus Save 25% on the game this weekend only.

Play now for Free!




-The Problem Solver

Buy the game if you don't already have it.

Be ready for the new DLC "Crash Course"


Crash Course:


Crash Course
Crash Course delivers new single-player, multiplayer and co-operative gameplay and bridges the storyline between the No Mercy and Death Toll campaigns in the original game. While containing both Survival maps and a Co-operative Campaign, the primary goal of Crash Course is to deliver a complete Versus mode experience in just 30 minutes, resulting in a streamlined version of the game's existing Versus campaigns.

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System Requirements
Minimum:

Supported OS: Microsoft Windows XP / Vista / Vista64
Processor: Pentium 4 3.0GHz
Memory: 1 GB
Graphics: 128 MB, Shader model 2.0, ATI 9600, NVidia 6600 or better
Hard Drive: At least 7.5 GB of free space
Sound Card: DirectX 9.0c compatible sound card


Recommended:

Supported OS: Microsoft Windows XP / Vista / Vista64
Processor: Intel core 2 duo 2.4GHz
Memory: 1 GB
Graphics: Shader model 3.0, NVidia 7600, ATI X1600 or better





-The Problem Solver

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