failed to load platform moduals?

hello, i recently bought halflife 2 for my PC at a car boot sale, it came with counter strike source so i thought id get it as i need counter strike for my gmod, i easily installed the game with no problems until i needed to validate it on steam, i put my pass in and then pressed log in, after a few seocnds a box came up with the title fatal error, failed to load platform moduels, i dont know what to do!

also wehn i try put in my code to validate the game i go on the link provided and it comes up on a french website!

any help will be high fived

The CD is probably already used by it’s original owner, you got conned.

The best thing you can do is contact Steam support with proof that you own the game, saying that you brought the game and the CD key was already registered. If you’re lucky they’ll de-authorize the original account and apply it to your account, don’t hold your breath though.

aww man, it wasnt really a con as it was 50p but still! man that sucks ill look into it right away

ok i jsut got an email back and this si what it says:
Hello Ben, Thank you for contacting Steam Support. The buying, selling or trading of Steam accounts, games or CD keys is a violation of the Steam Subscriber Agreement. Steam games cannot be transferred between users. We will not be able to assist you with this request. Please contact the seller about a refund. The Steam Subscriber Agreement can be found at: Additionally, please follow the link below for information: Title: Fatal Error: Failed to load platform modules Link: If you have any further questions, please let us know.

i mean, come on! does this mean that i cant use any game disk i havent bought new? thats utter crap! i buy disks cause there easier and often cheaper then buying the game off steam but now there saying i need to buy them off steam, this is terrible and i think steam should look into it