32 bit n 64 bit probs



Either run your program in compatibility mode, if it does not work use Windows XP mode in case you have Professional or Ultimate flavor, otherwise a free virtualization such as VirtualBox and use your old XP license with it.
 
What is the software? Simply stating that you have "software" isn't specific enough. The ONLY software that cares about 32-bit vs. 64-bit are drivers as the previous poster stated. Some software suites installed their own drivers, but if your software doesn't require it's own driver, then 64-bit isn't what's holding you up.