Most of them are capable of performing the same tasks and achieving the same goals. A programmer chooses one language by a simple preference. Each of these languages differ by the way they communicate with a computer however, and the commands that they follow are very specific. Not a single command of one language can be interchanged with the commands or language of another. ) aren't always compatible with the machines that we own. This is a common occurrence when newer pieces of hardware require the programming of a newer operating system. Sure, one could upgrade the operating system to accommodate the demands of a new piece of hardware, but trouble starts when that new operating system requires new hardware in return. And using older versions of programs could additionally reduce the costs associated with commercial versions. Up until recently, public opinion held little faith in freeware or open source software - often regarding it as low-quality knock-off's of better known commercial products. But if you take a good look at what's being offered at no cost, you may be in for a big surprise. If you find that you can't type information into one of these, you can effectively resolve the issue with a technician by calling it an input box, rather than a "white rectangle," or "place to put in text." Button - buttons perform a command after a user clicks them with a mouse. Problems occur when the text of a button is grayed out or if it doesn't appear to sink into the screen when clicked. But without seeing the extension, you wouldn't know it unless you double-clicked on it. The following list defines some of the most common extensions that you'll find on your computer. .au - This extension indicates a sound file. Most sound players will load up and play this kind of file. .art - This extension indicates an image file that was compressed with AOL (America Online) technology. You can do this through Internet Explorer by typing in the address and password required to access the router (the address and password required to access the router will be in the router manual). Connected to the network, each computer can send files back and forth, open programs on a remote computer, play the sound files and videos located on another computer, and share a single Internet account to browse the web, download files, or chat with someone in an entirely different country.