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. A virus that attaches itself to (infects) other programs is a file virus and activates the moment that an infected program starts. Or maybe that cool new programming language you've been dying to try requires more memory than what your computer currently has. Unless the activities on your computer are restricted to pure textual output (plain text files), your computer is going to get filled with a lot of "stuff" - stuff that can overfill a PC's capacity too much for the computer to function well. Remember that computers essentially run off of a series of commands and it's usually a smooth process. But when one command conflicts with another command - or when one command asks for a process or information that isn't available, the computer returns results that aren't useable. That's an error. A prime example of this kind of error is when users attempt to use software that isn't applicable for their system. Both Internet Explorer and the AOL service software can display this kind of file, however if you don't have AOL installed on your system, Internet Explorer will display it. .avi - This extension indicates a video file playable by most multimedia viewers including Microsoft's Media Player. .bmp - This extension indicates another image file that might have originated from Windows Paint program. Most (if not all) manufacturer's reserve a portion of cyberspace and dedicate it to support the products that they build. Microsoft's help desk is good example. 3. Fan sites. Fan sites probably isn't a good name for this resource, but you can find websites that are dedicated toward supporting the users of a particular software program or piece of hardware. Fortunately, computer systems are designed in a way that even a child can manipulate them. In fact, if you can remember that most systems are designed along the line of menus and the selections of a few options on these menus, you'll do just fine no matter how many buttons there are to push. For example, when you're faced with an electronic system, look for a main menu.