WinXP 64 does not have any 32-bit compatibility modes? That was something we had to deal with when we jumped from 16 to 32 bits. Win95 would do a lot of 16-to-32 bit conversion for you, a process known as "thunking". But sometimes you had to take some extra steps, creating a special shortcut to the EXE with advanced options selected to run in or emulate 16-bit Windows. It basically did a soft reboot into DOS, you could even specify DOS autoexec.bat and config.sys files to use for that game.
I assumed something like that would be built into WinXP 64, because I assumed we would need it to get some 32-bit games to run.