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Without a basic understanding of how computers and their files interact, you will not be able to understand the impact viruses and malicious code can have on a system.

A computer’s operating system and the programs that run on it are made up of individual files, most of which reside in directories or folders much like a filing cabinet. For example, most of the files associated with the Windows operating system might be found in a folder logically called Windows. Within the Windows folder are several subfolders (many of which also have subfolders) that help further categorize the files they contain. Files that don't reside in a folder or subfolder are said to be on the root of the drive.

The actual name of the Windows folder can vary from system to system. For example, someone installing the Windows XP operating system might choose a folder name such as WinXP. Because of this, %windir% is often used in technical writing to imply the name of the Windows folder, regardless of what that actual name might be.

Think of your home filing cabinet. Perhaps you have a file folder named ‘Bills' and inside that folder you have copies of individual bills you’ve paid. Perhaps you’ve even organized them using sub-dividers, so that the Bills folder is actually broken down into months or type of bills. Comparing that to a computer, the individual bills would be the files, the sub-dividers would be the subfolders, and the main folder ‘Bills’ would be a directory or folder found on the computer.

Terms to know:

• Files
• Folders
• Subfolders