How can i make my game to run in win 32bits?

My game is almost done. When i try to play it on win xp 32bits it says “mygame.exe” is not a valid win 32 application. But in the build options there are only two choices, win 64 y win 64x86. Is there any posibility to run my game on 32 bits?. Sorry aobut my english

Unity 4.3 has the following architecture options for the Windows target platform:

  1. x86
  2. x86_64

(1) is the 32-bit version.

Do you not have an “x86” option?