These Reports are only available if you have Logon Monitor installed.
I need to know if someone is trying to guess another user's password.
The Failed Logon Detailed Report monitors the failed logon attempts of a small number of users. The Report contains the username entered (or 'Invalid username' if the username is not recognised), the time of the failed event and the computer name.
I want to find out how many failed logon attempts there have been during the past week.
The Failed Logon Summary Report monitors the failed logon attempts of several users. The Report contains the username and the number of failed logon attempts. You must specify the top 'n' number of failed logons. By default, the 30 usernames with the most failed logon attempts are reported.