Log files, although sometimes difficult and certainly tedious to read, are the best way to expose the kind of detailed information needed to resolve operational issues. There are two categories of logs:
Event logs These are the binary logs generated by Windows.
Generic log These log files are specific to the application or are part of the application.
Windows SharePoint Services and SharePoint Server use both types to log informational, warning, or error data. A very important and extremely useful new feature is the ability to select the type of events you would like to log.
Browse to Diagnostic Logging ...