If you are a purist looking to experience CS 1.6 at its highest level, the community has largely moved toward modern, updated alternatives that are compatible with the latest Steam builds and offer better security.

If you are playing on servers protected by VAC (Valve Anti-Cheat), legacy versions of Zeroware are almost certainly "detected." Using them will lead to a permanent ban. Furthermore, third-party anti-cheats like GameGuard or EAC (used on some private leagues) will instantly block the DLL injection. The Technical "Fix" for Legacy Users

While players sought out Zeroware to dominate leaderboards, downloading and using it carried massive risks beyond just getting banned from the game. Malware and Viruses