To get window system info run
systeminfo
To get just OS info:
systeminfo | findstr /C:"OS" OS Name: Microsoft Windows Server 2008 R2 Enterprise OS Version: 6.1.7601 Service Pack 1 Build 7601 OS Manufacturer: Microsoft Corporation OS Configuration: Member Server OS Build Type: Multiprocessor Free BIOS Version: Phoenix Technologies LTD 6.00, 4/14/2014