This Modded UserSettings file i made will unlock all the achievements,
in every game in The Orange Box.
After you are done you will have the full 1000/1000GS
Resign then replace your UserSettings file with the Modded one.
Start up The Orange Box and pick one of the 5 games,
for Half Life 2, Half Life 2 EP1, Half Life 2 EP2, and Portal,
Just start a new game and once you get into gameplay hit the B Button,
and you will get all the achievements for the game you are playing.
for Team Fortress 2 start a system link game by yourself,
once you get into gameplay hit A and then B and all the achievements will unlock.