First of all this should probably be in a new thread.
Second I am no expert on 64 bit technology but from my understanding certain 64 bit processors and/or OSes are backwards compatible with 32 bit while some aren't. That might explain why some 64 bit systems will run 32 bit software and drivers and others won't. Also you can run a 64 bit system as 32 bit only by installing a 32 bit OS on the system. It just doesn't utilize the full capability of the processor.
If someone knows more about this than me and finds an error, please correct me.
Also Welcome to the forums.