EA released Battlefield 1942 as a free download back in 2012 (for the 10th anniversary). You don’t need a cracked key. The official version from that release doesn’t require a key to install or play single-player.
I keep seeing threads asking for a “Battlefield 1942 CD key” or “key generator.” Let me save you some time and potential malware trouble. battlefield 1942 key
(Mods: This is not piracy. The copyright holder, EA, released the game as freeware in 2012.) EA released Battlefield 1942 as a free download