Windows Server is a server operating system from Microsoft that provides a platform for running multi-user programs and networked applications critical to business computing. It offers ease of management through its interface and supports major web programming languages and databases. Windows Server 2008 R2 includes roles like DHCP, DNS, Active Directory, Hyper-V, and network, print, remote desktop, security, streaming media, terminal, and web services. It also includes technologies like Active Directory Federation Services, Active Directory Lightweight Directory Services, and Active Directory Rights Management Services.