Hawkeye22 :
As stated above, but why do you want to switch? Most 32 bit programs should work in Win7 x64. Older hardware that doesn't have 64 bit drivers is another story.
We have had problems getting decent 64bit drivers even for new hardware.
"most" 32 bit programs might run, but NO 16 bit programs will run, and if that is the software that you need, software that is irreplaceable, then you are stuck with a 32bit OS. I have said before that very few users will benefit from 64bit OS over the 32bit OS, but there are people for which the 64bit OS will cause problems.