Can't start TF2, Error: Setup file 'gameinfo.txt' doesn't exist in subdirectory 'hl2'. Check your -game parameter of VCONFIG setting.

[76561198070350982]

So here's the deal:
I'm not especially good with computers.
I have 5 HDDs and I had Windows 8 installed. After a short while I was annoyed and installed Windows 7 again. I had the SteamApps folder lieing around on one Hard Drive, and the normal Steam client folder on another Hard Drive. Neither of those were on C:\\. So in the progress of getting Win7 of course I formatted C:\. When it I started the computer everything seemed okay. But now when I start Teamfortress (SteamApps\common\Team Fortress 2) the hl2.exe it gives me: Setup file 'gameinfo.txt' doesn't exist in subdirectory 'hl2'. Check your -game parameter of VCONFIG setting. When I try to start Teamfortress in my Steam Client it gives me an option to pick a place where I want to install and wants me to download it all over again.

Well I would even do that, but my internet is so slow that it would take a whole lot of time. So since I aparently already got the game how do I get this back? Is there any way to start it?

Thanks a lot in advance! ♥

[cpipa]

it happan to me too but i have gmod and tf2 that say that when i tried to load