An event header contains the following information:
Date - The date the event occurred.
Time - The time the event occurred.
Source - The software module that logged the event, which can be either an application name or a component of the system or of a large application, such as a service name.
Category - A classification of the event by the event source. This information is used primarily in the security log.
Event - A number identifying the particular event type. The first line of the description usually contains the name of the event type. For example, 6005 is the ID of the event that occurs when the log service is started. The first line of the description of such an event is "The Event log service was started." The Event ID and the Source can be used by product support representatives to troubleshoot system problems.
User - The user name of the user on whose behalf the event occurred. If the event is not logged by a user, then the Security ID of the logging entity is displayed.
Computer - The name of the computer on which the event occurred.