I downloaded 2 files from a different website to play this game. However, when I try to install the game or the patcher thing, it won't let me get past the part where I need to specify where I want to install the files to. So my question is this: what EXACTLY do I need to do (download, install, etc.) to play this game? And yes, I do have a copy of Counter-Strike and Half-Life, both already installed.