Counter Strike Source problem: hl2.exe - Entry Point Not Found

Okay so let me tell you what's wrong with my css and what i did in attempt to fix it.
About three weeks ago i reinstalled my copy of windows 7 ultimate i did this because it was clogged with junk files and errors and i thought that if i reinstall it i would get a faster pc and it would be better for gaming.
when i reinstalled it i downloaded the latest drivers for my pc. And then i went to the windows.old folder wich still had some of my stuff i took out the css installation files and then partitioned the windows.old folder and deleted it.
I installed css and it worked fine i played all the time untill about two days ago i wanted to launch it and i got an error message saying:

hl2.exe - Entry Point Not Found
The procedure entry point SteamMasterServerUpdater could not be located in the dynamic link library steam_api.dll.

I was like how. I looked up on the internet on how to fix it and no results came up it was only similar stuff not the exact thing.
I unistalled css from my computer and went to kickass torrents to get the torrent file that's where i originally got it from,
I downloaded the file followed all the steps on how to install it did them and bam the same problem so i unistalled it once again.
So then i went to piratebay and downloaded the torrent for the file. Downloaded the file installed css looked carefully at the instructions followed them in the exact same order and bam exact same error message and i was really frustrated as i love playing it and i have mt christmas holidays now.
I went and downloaded the steam_api.dll file and it did not do anything i still got the same error message.
Anyone have any idea on how to fix this? 

Hello,

Did you also apply the included Crack file? It's important that you apply it to the correct folder.

Yes as i said i applied everything correctly i replaced the MasterServers.vdf file in the config folder with the one that was in the crack folder and set it to read only like it asked me to.

Nope no luck what really puzzles me is that it worked fine i didn't modify or configure my copy of windows 7 in any way. But it somehow stopped working anyways.

Thank you Carlos and Mr.Admin i will try and see if that works i doubt it would but i will tell you if it fixed anything. Anyways thanks for your help.

//EDIT

As i thought it didn't work oh man i don't know what i am going to do counter strike is my favourite game.

Thank you for all your help i'm getting a new computer and i will install css on that and hopefully it will work for now i guess i will have to play SA:MP.

Hello there,

Unfortunately I don't have many solutions for CSS either, it's a weird game.
Hmmm... when will you get your new PC? I'd love to know the result.