It's useless to keep this going, it requires a 64-bit OS, period.
There was a patch some time ago that brought the 6GB requirement down to 4GB, but the game STILL requires a 64-bit system and OS.
There is no legal way to bypass that, and people here won't offer you help for any illegal means you may or may not find, should there be any. Try getting a refund from where you bought it (good luck, if it's a Steam digital copy).
Also, for how harsh it may sound, it's time for you to move on; I'm assuming that, if you didn't jump on 64-bit already, you have an old PC (which means it'll also be a miracle if Ghosts can actually run at lowest settings, for how unoptimized it is on PC), and I know getting the money to buy a new gaming rig isn't that easy, but relatively any game from now on will probably require 4GB or more of RAM, 2GB or more of VRAM and a 64-bit OS.