Software needed to automate an existing Windows application as if a person were running the program, pressing keys, and mouse clicks.

How about : iolo MacroMagic 4.1t Pro - Useful Tool for Automation
info :
Macros to do anything you can, but faster!
Macro Magic's powerful visual tool palette allows you to do anything you desire with your macros, but faster and more reliably! You can send input, run programs, copy, move, rename and delete files, wait for windows to appear, run existing macros, minimize and maximize windows, restart or shutdown your computer, connect to the Internet, access web sites, send email, copy files via FTP, gather user input for use later in your macro, and much, much more. With Macro Magic's awesome palette of actions and advanced features, the possibilities are endless.

Run your macros any way you like with a variety of triggers!
Macro Magic provides numerous ways to launch your macros. HotKeys allow you to specify specific key combinations to launch your macros, such as specifying Ctrl+Shift+I to execute your macro. MagicKeys™ are small bits of text that Macro Magic can detect to launch your macro. For example, you can have Macro Magic type your email address for you every time you type the word "email1". Macro Magic allows you to create Windows Shortcuts to launch your macros. Using Windows Shortcuts, you can use the Windows Task Scheduler to schedule your macros. Macro Magic also provides automatic triggers. These include launching your macro whenever a certain window appears, and launching your macro after your computer has been idle for a specified amount of time. Macro Magic gives you the ability to run your macros however you wish.

Keeping your macros organized is easy with Macro Magic!
With the powerful features of Macro Magic, it's easy to see how you could create dozens, if not hundreds of macros to perform your most common, redundant tasks. With Macro Magic, organizing your macros is easy. Macro Magic lets you create macro lists, allowing you to keep macros for certain applications separated from your other macros. Macro Magic is capable of automatically loading a certain list when a specific application appears. You can even make your macros available only to a specific program. You have total control over your macro organization.

Share your macro lists with Macro Magic's full network support!
Macro Magic offers full support for networks. Share your macro lists, or access shared macro lists! Centralize your company's macros to one location and make them available to the whole company. Additionally, Macro Magic incorporates remote installation and uninstallation capabilities, as well as provides secure access to macro lists to prevent unauthorized changes. Distribute Macro Magic across your organization today and start cutting back wasted time immediately
With Macro Magic, you can record your keystrokes and mouse movements and save them as a macro for later use. In addition to recording your keyboard and mouse actions, Macro Magic's extremely powerful Macro Builder empowers you with the ability to create a series of actions step-by-step. The Macro Builder presents powerful flexibility and functionality.

With the Macro Builder you can send keystrokes and other input, run programs, copy, move, rename and delete files, wait for windows to appear, run existing macros, minimize and maximize windows, restart or shutdown your computer, connect to the Internet, access web sites, send email, copy files via FTP, and gather user input for use later in your macro. Additionally, Macro Magic introduces options to insert delays, prompt the user to continue macro execution, play sound files on your computer, control existing windows, repeat portions of your macros, create/increment counters, and embed comments within your macro.

The Macro Builder allows you to insert steps before existing steps, append steps to the end of the macro, move steps up or down the list, enable/disable any step in the macro with a single mouse click, play the entire macro or just selected portions, pause macro execution, stop macro execution, or import existing macros. Macro Magic's feature rich Macro Builder offers everything you need to create and edit powerful, time-saving macros.

Download
http://dl.iad.downloadhosting.com/download/iolo/mmagic.exe

The best program for this is called Auto It 3. By writing simple scripts you can activate, close, minimise and maximized windows. You can also send keys, mouse clicks and more. The language is pretty strait forward and the program give lots of examples to help you.

http://www.autoitscript.com/autoit3/index.php

Hope this helps,
Rick G

Macro Express can do all of those things you specified plus it's very highly rated.  I use it all of the time.

http://downloads-zdnet.com.com/Macro-Express/3000-2094_2-10356877.html?tag=lst-0-1