The keylogger can be enabled by selecting the Enable checkbox and disabled by deselecting the Enable checkbox. The log is put in the large textbox, which can be cleared by pushing the Clear Box. It is as simple as that. You may worry that the keylogger is a security concern, but it is actually just a novelty. I have taken various steps to ensure that it cannot be exploited easily. First, the keys logged will not be saved to your hard disk. Once you push the Clear Box button, the log will be gone for good. Next, while the checkbox is not pushed, no keys whatsoever will be logged. Also, the log will only store up to the last 100 characters. Last, the window is set as Always-on-Top, so unless it is minimized, it will be always visible.
Not to be confused with the Window Controls, the Windows Controls allow you to control Windows® as a whole. The Log Off button lets you log off of Windows, the Restart button lets you restart Windows, and the Shutdown button (not surprisingly) lets you shutdown Windows.