Half-Life 2 Episode One - Full Game

System Requirements of Half-Life 2 Episode One:

Operating System: Microsoft ® Windows ® 98 / ME / 2000 / XP
DirectX ® - Processor: Intel Pentium ® or Athlon 1.2 GHz
Memory: 256 MB
Hard Drive: 5GB
Video: video card, compatible DirectX ® 7

Here is the Download Link:

Half-Life 2 Episode One Part 1
Half-Life 2 Episode One Part 2
Half-Life 2 Episode One Part 3
Half-Life 2 Episode One Part 4