Microsoft Hyper-V Server 2008 R2 SP1 2008 R2 SP1

Good operating system, works fast, Longhorn project.There is such a drawback:antivirus program can only be installed for servers, Acronis is also only server. But the Defender from Microsoft works very decently. In other respects this system does not differ from Win7, but disk memory for the system partition uses only 5.5 GB. By installing Stardock's Aero desktop, it is almost Win7 but with less demand on computer resources. For old computers on Std4 and Athlons it's just what you need.