dll - This extension indicates a Dynamic Link Library which may contain additional programming code for software. Many different programs often share Dynamic Link Libraries and you'll find a bunch of them in the Windows/System directory (but don't ever delete them)! .exe - This extension indicates a program or an application like Microsoft Word, Internet Explorer, or Outlook Express. Compared to Microsoft's Access database program, its user-friendly Address Book is a Godsend to new computer users. Calculator. Calculator has been a Windows accessory even from its first debut in Windows 1.0. For the life of us, we can't figure out why anyone other than a rocket scientist would want to install a different version than this free one that comes pre-installed. 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. 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. No motor equals no computer. Keep your computer's fan clean by preventing the fan from getting dirty or dusty in the first place. Use the computer in a dust-free environment and never smoke around it. Nicotine and tar mean certain death when it comes to computer fans, however should you find a need to clean the fan, do so with extreme care. For those entering the United States from a foreign country, users will appreciate how Windows grants use of keyboard layouts native to their original language. Other uses will appreciate the different selection of cursors and the ability to add additional ones. Passwords. Since the computer in use may be shared with others, Passwords gives the almighty administrator the means to determine whether all users will share the same preferences and desktop settings or if users can customize preferences and desktop settings.