To parse one file you would do something like this (just change to the path and name of your .evt file and update the EventID)
Logparser -i:EVT "SELECT * FROM system.evt WHERE EventID=15" -o:DataGrid
To search more than one file, use the multiplex feature. You could do something like:
Logparser -i:EVT "SELECT * FROM d:\myEventlogs\*.evt WHERE EventID=15" -o:DataGrid
Let me know if this works.