32 bit software should run out of the box by: Anonymous
There's no reason for 32 bit Windows software to not run on Vista 64.
However, if you're trying to reinstall software that uses a 16 bit installation program - it won't work. In that case, it's not the 32 bit software, it's the obsolete 16 bit installer the vendor used.
It's also possible you have software that's dependent on old style and no longer supported drivers - again the vendor needs to step into the 21st century.
Finally, certain older software that might have run on XP may not run on V64 because it breaches fundamental operating segregations or relied to specifically on knowledge of internal structures that had no official published interface and therefore shouldn't have been used and that have since changed.
However, in general, any normal 32 bit windows app should be directly runably on V64.
What are some examples of apps that you're having trouble with?