Okay - we're assuming that the reasoning behind hiding extensions is a "user-friendly" one because we just can't come up with any other reason for hiding them. No harm could ever come from seeing an extension, but plenty could be learned from it. Fortunately you have this article to guide you through some of the most common extensions that you'll run into. But Windows Media Player, also free and pre-installed, does a fine job at transmitting Internet-bound sound and video. With this application, you can easily listen to .wav files, .midi files, and even tune into a little Internet radio if you like. System Tools. Although there are too many to list here, Windows provides more than a handful of useful utilities that will monitor system resources, organize files, repair damaged disks, and more. Hackers look for things like full names, social security numbers, phone numbers, home addresses, work-related information, and credit card numbers. If these things aren't saved onto a computer, there's nothing critical to worry about other than restoring your computer to a non-virus condition. 3. Don't open files without scanning them with an anti-virus/anti-spyware program. But sometimes Windows' Add/Remove Programs isn't enough. Although this software does a pretty good job of removing unwanted programs, it can leave some files behind even after a complete uninstall - files which become orphan files. And it's these orphan files that can really clutter up a hard drive and shorten the life of an otherwise, young and robust PC. Some files compress better than others and in some instances, you may not notice that much of a difference. The files that compress the best are images, documents, and multimedia files. Executable files (files that end in an .exe extension) don't compress that well, however when they're archived with a sizable number of other files, they compress rather well. All this is possible from making just a few changes in your computer's current configuration. Your computer's main configurations are housed in Windows Control Panel. Within this small section of Windows, you can make some major changes from the way that your computer looks to the way that your computer responds to the people who use it.