Windows 10 can run on both 32-bit and 64-bit processor architectures. If you have a computer with a 32-bit setup, you can upgrade to the 64-bit version without acquiring a new license. The only caveat ...

Seeing that there is a good possibility Macs could become 64bit soon I thought It would be nice to have a discussion on 64 bit software. I didn't want to stick it in with the 64 bit Hardware ...