If you build a virtual machine using Hyper-V and the standard Network Adapter, you are installing a synthetic network adpater. That adapter does not typically have drivers included with the operating system (Windows 7 and Windows 2008 R2 are exceptions). In order to get a driver for the network adapter, you must install Integration Services.
To install Integration Services, click the Actions menu option from the Hyper-V Manager MMC. In the dropdown menu, select Install Integration Services option
Follow the prompts on the screen to select any custom options
Once you are finished installing the Integration Services, you will need to reboot the virtual machine.
NOTE: you can only install Integration Services for supported operating systems.

