An application in Windows NT and Windows 2000. Event viewer lets you view logs of events that have happened on your system.

The events are arranged into three categories. Events in the applications category are eventsgenerated bythird party applications on your computer. These could include a word processor, web browser or some kind of server. Events in the system category are messages from Windows itself. These could include information about services failing to load, low disk space on a volume or errors from other windows components. The security category lists events dealing with the security subsystem. This includes failed login attempts, or a user's attempts to access a resource he does not have privilege to access. The security category may only be viewed by members of the administrators group.

There are five levels of severity an event may have. Information describes an informational event, this is not necessarily a problem with the system. Informational events include the starting and stopping of various services, the loading of various drivers, and establishing of network connections. Warnings are indicators of possible future problems. Application errors are usually marked as warnings. An error is a serious event that prevents a program, service, or Windows itself from functioning normally. Errors are the most serious type of events, and should be dealt with immediately.

In the security category, there are two additional types of events. Success indicates a successful security audit, such as someone successfully logging onto the system. Failure indicates a failed security audit, such as someone failing to login properly or attempting to access a resource they do not have access too.

The event viewer is a very useful application for troubleshooting problems with the system. It is usually a good idea to review the event logs regularly. You should make a note of any warnings or errors you find, and resolve the problem ASAP.