Silly opposing force

[prophecy holder]

I installed Opposing force yesterday for the first time in years, when it finished an error appeared and then dissapeared quickly when it got done. I payed it no mind and decided to Ifired up the game, boot camp, new game and mutliplayer was grayed out so I reinstalled it. Second time around the areas are not grayed out but everytime I try to start anything an error message appears saying "Pak0.pak is not a pak file" then it quits out.

I tried to ditch the manual install and try and tegister it through steam, it keeps saying the CD key is invalid even though when I enter it through the usual way it says it's valid. For ♥♥♥♥s and giggles I tried the same with Half life and it says another account already owns the "Half life complete pack". Sorry steam you are wrong, I bought Half life in 1998 when it was first released and never bought a "complete pack".

I don't really care for the Half life but I do want to play opposing force, so what gives?

Forgot to add: It takes regular Half life about a minute to install, opposing force on the other hand takes 10-15 minutes to install.

[Marcem7121]

Someone probably used a keygen and stole your Half-Life key, sort it out with steam support and you get the entire half-life 1 series and a few extras.

[rivaldid]

have you never lent the game to friends?
are you sure you have not registered the game on another steam account?
i guess you could send to steam support a photo which shows you own the original game to have back it.

[pumpmoreoil]

I tried to ditch the manual install and try and tegister it through steam, it keeps saying the CD key is invalid even though when I enter it through the usual way it says it's valid. For ♥♥♥♥s and giggles I tried the same with Half life and it says another account already owns the "Half life complete pack". Sorry steam you are wrong, I bought Half life in 1998 when it was first released and never bought a "complete pack".
I have found that if you register your CD-key for Opposing Forces, Blue Shift, or Half-Life 1 it now installs as the Complete Pack and you get the other titles whether you had them or not. I had registered Half-Life to an older Steam account of mine that I can no longer remember. So I was dismayed when I tried adding it to my current account and received the "already registered" message. I resolved to buy another copy via Steam but before doing that I attempted to register Blue Shift and Opposing Forces to my current account. Voila! The O-F key was enough to activate the Complete Pack and I have a working copy of my Half-Life 1 again. Long story short... Any H-L1 product key registers as the Complete Pack on Steam. That is why you are receiving that message.