How do you run a 32-bit program on a 64-bit Windows Vista computer?

It is impossible to run 64 bit applications on a 32 bit based system. You can upgrade to a 64 bit version of Windows XP, Windows Vista and Windows 7... unless you use a Virtual Machine to run a 64 bit OS. Note that this could be very bad to use if your computer is physically not capable of running a 64 bit OS.