[intrestedviewer]

you can buy half life. This gives you the mod versian of CS. It wont come with your half life cd but you can download it. If u do buy or have half life and want to play online u have to download the latest patch hl1110.exe - English retail full v1.1.1.0 patch. Once u have downloaded the half life patch and installed it you can download CS, DoD, Team Fortress and others.
Of course you need the latest versians of the mods, and make sure your downloading the mod versian, not retail. Retail is if u bought the mod as a stand alone game. And make sure that all patches u download are for your country. if u live in USA and download the french, italian etc. versian it wont work.
I suggest u buy half life not the CS retail, u get more out of half life cause of the limitless mods and its only 15 bucks. CS retail is like 20 ed:
To get files u can try gamespy or 3d gamers or fileshack.