This article describes some common mistakes that you must avoid when you write a service. The article also suggests best practices to follow when you create Microsoft Windows Services. A Windows Service is a program, a routine, or a process that performs a specific system function to support other programs, particularly at a low (close to the hardware) level. Examples of Windows Services include server products, such as Microsoft Exchange and Microsoft SQL Server, and other client applications, such as Windows Timer that sets the computer clock. Windows Services are automatically started when you start the computer and do not have a user interface.