Powered Keylogger lets you instantly turn on/off keylogging process. In order to stop recording the logs, please, unhide Powered Keylogger application (if it isn't already done), select the "Options" Navigation Toolbar button and press "Stop recording" button:

You will be prompted to confirm that you want to stop keylogging process, and to proceed click "Yes". The "Stop recording" button will change its state to "Start recording" which you may click to enable recording once again.

However, if you would like to stop monitoring for particular log type then unmark corresponding checkbox in Navigation Pane and press "Apply changes" button.
Note: After system reboot the keylogging process doesn't start automatically. You will have to click "Start recording" button (go to "Options" in Navigation Toolbar).