However, such accidents do not actually erase the contents of the hard-disk drive files until new data is written to the sectors containing these files. With software such as the Norton Utilities, Mace Utilities, or PC-Tools Deluxe, the data stored in these areas can often be restored, meaning that you can recover most, if not all, of the data.

Unlike formatting a hard-disk drive, formatting a diskette completely erases all the data on the diskette unless you use the diskette formatting program included in the Mace Utilities.

For a complete description of data recovery procedures and the software needed to perform them, see The Paul Mace Guide to Data Recovery, published by Brady.

Cleaning System Components

An exhaust fan in the power supply cools the power supply and computer by drawing air in through various openings in the computer and blowing it out the back. However, the fan also draws dust and other particles into the computer, causing contaminant buildup, which results in an increase in the system's internal temperature and interferes with the operation of various system components.

To avoid these conditions, Dell recommends keeping your work environment clean to reduce the amount of dust and dirt around the computer, thereby reducing the amount of contaminants drawn into the computer by the power supply fan. In particular, you should keep the exterior of your computer and monitor clean, and you should use a commercially available diskette-drive head- cleaning kit to remove contaminants inside your diskette drives.

Recommended Tools and Accessories

Dell recommends that you use the following tools and accessories when you clean the computer:

A wrist grounding strap - The proper use of a wrist grounding strap reduces the effect of electrostatic discharge (ESD), which can damage certain computer components. To use a wrist grounding strap, place the strap around your wrist and attach the other end of the strap to an unpainted metal surface in the chassis, such as the power supply bracket, that is connected to chassis ground.

A liquid dishwashing detergent - Use a mixture of one part liquid dishwashing detergent and three parts water to clean the exterior of the computer, monitor(s), and keyboard. You can also add fabric softener to produce an antistatic solution that prevents dust from being attracted to the monitor screen.

A soft, lint-free cleaning cloth - Moisten the cleaning cloth with the dishwashing detergent solution to clean the exterior of the computer system.

A nonabrasive diskette-drivehead-cleaning kit - Dell recommends that you use a kit that contains pretreated diskettes in individually sealed packages. These kits ensure that the cleaning solution is applied evenly over the entire diskette-drive head surface, and they prevent contamination of the heads by exposure to foreign substances.

A small vacuum cleaner with a brush attachment - Use the vacuum cleaner to remove dust and dirt from the exterior of the computer and keyboard.

Cleaning the Computer, Monitor, and Keyboard Exteriors

A conventional monitor or keyboard cover minimizes the accumulation of dust and other debris inside the monitor and keyboard when they are not in use. Also, commercially available keyboard membrane covers make it possible to use the keyboard while providing protection against foreign particles.

However, regardless of any protective covers, the monitor and keyboard must be cleaned occasionally. To clean the exterior of the computer, monitor, and keyboard, follow these steps:

1.Turn off the computer, monitor, and any other attached peripherals, and disconnect them from their power sources.

2.Use a vacuum cleaner to remove any dust from the slots and holes on the computer and between the keys on the keyboard.

3.Moisten a soft cleaning cloth with a solution of three parts water and one part liquid dishwashing detergent. Do not soak the cloth in the solution; you must not let the solution drip inside the computer or keyboard.

4.Use the moistened cloth to wipe the computer cover, the keyboard, and the exterior of the monitor, including the screen.