As previously mentioned, preventing dust from entering the computer is extremely important and will reduce the need to open and dust your system in the first place. The severity of outside elements (smoking, humidity, pets, etc.) will ultimately determine how often you'll need to de-dust your machine. 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. Why viruses exist remains a mystery, however we had privy access to the mind behind a virus programmer who explained his motivation behind his destructive inclinations. Apparently, this person had a deep grudge against a popular online service which shall remain unnamed. In this hacker's mind, the online service failed to do a quality job in protecting children from online smut and as retaliation, he created and distributed a virus to as many file libraries of this service as he could. 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. So with WordPad having the ability to read and create rich text; embed objects (sound, pictures, and video); and manipulate fonts, we have to wonder if other word processors, which do the same thing, are really necessary. Although WordPad is certainly no match for Microsoft Word's internal spell and grammar checker or Word's Internet linking capabilities, we believe it's a great introduction to word processing in general for computer novices. In programming, it's sometimes required to work with unknown pieces of data. That's when conditions come in handy. Conditions allow a program to perform an action based on the outcome of a previous command.3 Using this type of instruction, we could instruct a program to do one thing if the "x" variable in our latter example turned out to be 7 days, and then do different thing if the variable turned out to be 3 days.