I didn't want to install the plugin in Firefox, so I continued the download using IE 7 instead.
I just re-opened the The http://www.microsoft.com/downloads/details.aspx?FamilyId=21EABB90-958F-4B64-B5F1-73D0A413C8EF&displaylang=en">VPC image in IE 7. If you're already in IE 7, then go go the next step.
If you'd rather continue in Firefox, then you'll need to install the plugin there. I didn't detail the steps to do that. Return to step 5 when you've validated that you're running Windows.