In Windows Vista:
1) Control Panel, Classic View, Add Hardware

2) Device Manager, right click on root node and select Add Legacy Hardware

In Windows 7:
1. Click the Start menu.
2. Search for “cmd".
3. Right-click on “cmd” and select “Run as Administrator”
4. Enter “hdwwiz.exe”

From that point on it's the same approach as under Vista, i.e.:
1. In the "Welcome to the Add Hardware Wizard", click Next.
2. Select "Install the hardware that I manually select from a list (Advanced)" and click Next.
3. Scroll down and select "Network adapters" and click Next.
4. Select under Manufacturer "Microsoft" and then under Network Adapter "Microsoft Loopback Adapter" and click Next.

I hope this help someone

Thanks