Re:32bit windows runs 16bit apps (Score 3, Informative)

All a 64-bit OS does it run applications built with 64-bit libraries. If 1 link in the chain of code from the application itself, down to the lowest level library linked in, is 32-bit, you generally need to build the whole application 32-bit. Often, a 64-bit does not automatically install all the 32-bit versions of the system software (and why would it, since the vendor wants to spend most of their time developing and testing the 64-bit installation) ergo, the 32-bit software won't run.

P.S. In my experience, it is almost never worth it in terms of performance vs. sotware availability to run a 64-bit desktop. People do it to look macho, then get incensed when all their favorite consumer-grade software won't work.

Cheers,