If a Windows 7 PC with “unknown” (aka Driver missing) will simply connect to Windows Update, check if a matching driver is found and install it. This works fine when using this at home, but it does not work if you are inside a corporate network.

In this case, a Windows Server Update Services (WSUS) is used and it does not contain any drivers. Therefore, you need to manually download the drivers you need, put them in a folder and then use DPinst.exe to install the drivers.