Starting with EventSentry version 2.70 you can view the native event log files (usually with a .evt extension) with the built-in event log viewer of EventSentry. Simply right-click the "Event Log Viewer" container and select "Open Log File".
If you are running EventSentry v2.60 or earlier then you will need to open the event log files with the Windows Event Log Viewer.
The Windows Event Log Viewer is located in the "Administrative Tools" folder.