I live in an area where many old people are. Many such wonderful people still have old computers running old software. However, they slowly start upgrading their computers and operating systems to the latest and greatest 64-bit Windows 7 systems – but they want to use their beloved old software. Here's the problem!
The other day I set up a new Windows 7 machine for a client. He was very happy and then said, "Okay, let's install my Greetings CreataCard Gold 5 and Hoyle Card Games for my wife now." He and his wife have been using these programs for years and could not spare them.
Well, as you probably can imagine, these two programs will not install it. Both older programs are 16-bit and do not install the 64-bit Windows 7 operating system. If my client bought a 32-bit Windows 7 operating system, he could run his programs in compatibility mode but this feature will not work on 64-bit Windows 7.
So the guy was very frustrated, "cool like cucumber" because I knew there were several great free virtual machines that let you run older 16-bit programs in the 64-bit version of Windows 7.
DOSBox (DOSBox is a DOS emulator and only 16-bit MS-DOS programs and not 16-bit
VirtualBox ("virtual machine" that allows an unmodified operating system to run all installed software in a special environment, in addition to its existing operating system.)  3) VMware Player ("virtual machine" that runs an old Windows operating system without disturbing the original operating system
programs on the brand new operating system