Hi,
to virtualize a physical machine, two important components are needed:
1- source (your Windows 7 PC)
and the
2- destination (virtual environment, esxi vmware, etc ...)
So, like Storage, the virtual environment can also have a NAS connected.
what is your virtual environment? you want to create your virtual machine on?
you can attach some pictures of how you are configuring the vcenter converter to do the conversion, so we can help you better.
ARomeo