On Windows Server 2012 R2 you should: 1) insert virtio-win ISO into optical drive, 2) browse content optical drive for find NetKVM driver for your operating system, right click on netkvm.inf and select Install. On Windows Server 2008 R2 after select Install from right click on netkvm.inf you see error The INF file you selected does not support this method of installation.
1) On virtual machine, open Device Manager
2) Right Click on Other Devices - Ethernet Controller and select Update Driver Software
3) On screen How do you want to search for driver software? select Browse my computer for driver software - Locate and install driver software manually
4) On screen Browse for driver software on your computer specify path for NetKVM driver on optical drive, e.g: D:\NetKVM\2k8R2\amd64 and click Next
5) On screen Installing driver software you agree of installation driver from Red Hat Inc. and wait for end of installation.
6) In Device Manager you should appear Network adapters \ Red Hat VirtIO Ethernet Adapter