Through Display Properties, a user can change the background of the Windows Desktop, add a screensaver, change the overall color scheme and fonts of Windows, and adjust a computer's color depth and/or resolution (screen area). Not just a bunch of preference settings, display properties help individuals who have to deal with visual problems. Conditions allow a program to perform an action based on the outcome of a previous command.3 Using this type of instruction, we could instruct a program to do one thing if the "x" variable in our latter example turned out to be 7 days, and then do different thing if the variable turned out to be 3 days. We described shareware in another article, but because both commercial software and shareware require payment, they're the target of pirates who seek to make these kinds of programs free to use. Depending on their binding legal agreements, licensing typically allows the use of a single program on a single computer. Let's say that every day we need to load up the Yahoo web browser, Microsoft Word, and then the calculator that comes with Windows. Instead of doing this by hand, we could write a batch file to do it for us. First, we'd load up Notepad and type in the following: START "http://www.yahoo.com" START "c:/program files/microsoft office/office/winword. It manages the activity of every component and then displays that activity as a user-friendly interface (GUI). It keeps track of where things exist on a computer's hard drive as well. But perhaps most importantly for the end-user, the operating system is responsible for translating commands issued with a keyboard and mouse into binary code (010110101 stuff) that can communicate with a set of speakers, a printer, a scanner, and more. We download files from software libraries, ftp directories, YouTube and Google Video, MP3 sites, and we download files sent to us as email attachments. Being so popular an activity, it's imperative that you compress the files destined for another computer. File compression combines a number of different files into one file, and it can also significantly reduce a very large file to a smaller one.