Microsoft Servers (previously called Windows Server System) is a brand that encompasses a line of Microsoft server products. wikipedia.org

Windows Server is a brand name for a group of server operating systems released by Microsoft. wikipedia.org

VMware ESX is an enterprise-level computer virtualization product offered by VMware, Inc. ESX is a component of VMware's larger offering, VMware Infrastructure, and adds management and reliability services to the core server product. wikipedia.org

Microsoft Exchange Server is the server side of a client_server, collaborative application product developed by Microsoft. It is part of the Microsoft Servers line of server products and is used by enterprises using Microsoft infrastructure products. wikipedia.org

Technical support or tech support refers to a range of services by which enterprises provide assistance to users of technology products such as mobile phones, televisions, computers, software products or other electronic or mechanical goods.

Microsoft SQL Server is a relational database management system developed by Microsoft. wikipedia.org

Microsoft SharePoint is a Web application platform developed by Microsoft. wikipedia.org

Software as a service (SaaS) sometimes referred to as "on-demand software", is a software delivery model in which software and associated data are centrally hosted on the cloud. SaaS is typically accessed by users using a thin client via a web browser. wikipedia.org