Viruses that destroy data are known as Trojan horses, viruses that explode their attacks are called bombs, and viruses that duplicate themselves are called worms. Some viruses are a combination of each, however they can be further identified according to where they're located on a computer. A virus originating from the boot sector of a computer is a boot-sector virus and this nasty devil does its dirty work the moment a computer is turned on. This causes the computer's motor to work harder - and a harder working motor can raise the electric bill! Worst case scenario: the motor can overheat and stop working as well. No motor equals no computer. Keep your computer's fan clean by preventing the fan from getting dirty or dusty in the first place. Since we want these programs to load every day, we could create a shortcut to this file and then place the shortcut inside our computer's Start Up folder. That way, these three programs would load every time we turn on the computer. If you wanted these programs to start minimized, you could type the following into a batch file instead: START http://www. That dot and group of three letters is known as an "extension," and the extension explains what kind of file it is. A file could be a plain text file, an image, a sound, a video, or program. 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. Open Source Software If you've spent any lengthy amount of time on the Internet, you've probably heard of open source software but might not have fully understood what it is and why it even exists. This article will describe this recent phenomenon and describe some of its benefits for the software using community. 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.