Keep your system's logs from being tampered with.
Windows has some very powerful logging features. Unfortunately, by default the event logs are not protected against unauthorized access or modification. You may not realize that even though you have to view the logs through the Event Viewer, the event logs are simply regular files just like any other. To secure them, all we have to do is locate them and apply the proper ACLs.
Unless their location has been changed through the registry, you should be able to find the logs in the %SystemRoot%\system32\config directory.
The three files that correspond to the Application Log, Security Log, and System Log are AppEvent.Evt, SecEvent.Evt, and SysEvent.Evt, respectively. Now, apply ACLs to limit access to only Administrator accounts. You can do this by bringing up the Properties dialog for the files and clicking the Security tab. After you've done this, remove any users or groups other than Administrators and SYSTEM from the top pane.