First of all, your client would need to have permanent internet connection with fixed public IP address. The home type ADSL connections would not work.
Second, your client should set up VPN service that will accept incoming VPN connections. Microsoft Windows Servers have this feature built-in, in "Routing and Remote Access Server (RRAS)". Third party solutions are also available.
When VPN server is established, you can configure VPN "dial-out" connection on your Windows 7 computer. This connection will connect via Internet to the VPN server at your client. Your Windows 7 computer will then have access to your client's internal
network. When you have access to internal network, you woul use RDP connection to your client's work computer(s).
If your client does not have permanent internet connection, they may try to set up modems. This is somewhat older technology, but it should still work. Again with Windows Servers RRAS feature, a modem dial-in service can be established. Of course,
in that scenario, Windows 7 computers would have to use modem connection, not Internet.
Microsoft is conducting an online survey to understand your opinion of the Technet Web site. If you choose to participate, the online survey will be presented to you when you leave the Technet Web site.