Event viewer maintains logs about program, security, and system events on your computer.
You can use event viewer to view and manage the event logs, gather information about hardware and software problems, and monitor windows security events.
These logs are presented in reverse chronological order, so the most recent events are at the top and as you scroll down you'll move back in time.
To open event viewer:
Start > Control Panel > Administrative Tools > double-click Event Viewer.
Or:
Run... > eventvwr.msc
Application, security and system logs:
With Event Viewer, users can monitor events recorded in the Application, Security, and System logs:
Application log:
Application log contains events logged by applications or programs.
Eg: a database program might record a file error in the application log. Program developers decide which events to monitor.
Security log:
Security log records events such as valid and invalid logon attempts, as well as events related to resource use such as creating, opening, or deleting files or other objects.
An administrator can specify what events are recorded in the security log.
Eg: if you have enabled logon auditing, attempts to log on to the system are recorded in the security log.
System log:
System log contains events logged by Windows system components.
Eg: the failure of a driver or other system component to load during startup is recorded in the system log.
