A Form Filler is a freeware that watches for Windows or alerts, and takes pre-defined action on them immediately. For example, it can watch for login window of Gmail, and automatically fill your credentials in that. Or, it can watch for any alerts that come during system start-up, and automatically take care of them.
Basically, you can define software windows that you want to keep track of, and then specify the keystrokes that you want to send to those Windows. A Form Filler will then keep on running in the background. Whenever it finds that any of the pre-defined window has come up on screen, it will immediately send keystrokes to it that you had earlier provided. You can define as many windows as you want, and then specify individual keystrokes to send to each window.
Note that A Form Filler is not an advanced automation software like Mouse Keyboard Recorder, or TimeComX. However, it performs the specific task of proactively monitoring for pre-defined windows, and then automatically takes action on them.
You can check out a detailed tutorial here about how to use A Form Filler. A big limitation I found with A Form Filler is that you can specify only keystrokes that you want to send to a Window, and not mouse clicks. Of course, in most of the cases a mouse action can also be converted into keystrokes, but I would have found that feature more useful.
Nevertheless, A Form Filler is a good program if you want to automatically take actions on pre-defined windows.