Changing the default location the Virtual PC uses for virtual machines

A regular question I hear is “How can I stop Virtual PC from storing all of my virtual machines in the ‘My Virtual Machines’ folder in ‘My Documents’?”.  The answer is simple – but obscure.  To change this you need to create a system environment variable called ‘MYVIRTUALMACHINES’ with a value of the path that you want Virtual PC to use for the default location for storing virtual machines.