If you have the game installed but lost the physical key, it is historically stored in the Windows Registry under: HKEY_CURRENT_USER\Software\Valve\Half-Life\Settings in a file or string named "Key". Modern Compatibility Half-Life - Counter-Strike CD Key | PDF - Scribd
If your goal is to experience the specific 1.4 version (rather than just playing CS in general), you generally have two options: counter strike 1.4 cd key
If you want to play Counter-Strike 1.4 today, skip the key resellers. Grab a Half-Life license, search for "CS 1.4 revival launcher," and get back to stacking boxes in cs_militia . If you have the game installed but lost