Most personal computers (PCs) are relatively easy to open. At least every few months, open yours and use canned air to carefully remove any dust. Electronic devices are notorious dust collectors.

Disassemble your computer:

1. Disconnect the power cord and external cables from the computer.
2. Loosen screws on the rear of the computer case.
3. Lift or slide the case from the frame.
4. Reinstall by reversing the procedure, making sure the housing doesn't pinch any cables.

When any part of a computer system fails, first check the cable connecting that part of the computer.

Check external cables:

1. Verify that the cable isn't loose, defective, or plugged into the wrong socket.
2. Unplug and reconnect the cable several times, making sure that all pins and holes match up. If you see corrosion, use an electronic contact cleaner following instructions on the can.
3. Test the cable for continuity with a multimeter.
4. Hand-tighten any connection screws or wires that hold the cable to the computer.
5. If the cable still doesn't work, take it to a repair shop for testing and, if needed, replacement.
   Diskette (erroneously known as "floppy") drives are so inexpensive that many people opt to replace them rather than repair them. If you're planning to replace it anyway, consider repairing it yourself; it may work or it may not. Diskette drives include two small motors, a read/write head, and probably a drive belt. If the drive can format a new diskette, but can't read it, the problem is probably a dirty or misaligned head.

Service a keyboard:

1. Disconnect the keyboard from the computer and turn it upside down. Remove the assembly screws and pry apart the top and bottom housings.
2. Carefully lift off the top housing and either shake out or blow out debris with canned air. Use an electrical contact cleaner to remove any residue or corrosion.
3. If the keyboard still doesn't operate properly, replace it.

Service a mouse or a trackball:

1. Unplug the mouse and turn it upside down. To remove the trackball, press the ball-cage housing cover clockwise or forward, depending on the model. (Most mice have instructions and arrows on the bottom.)
2. Remove the track ball and clean it with a lint-free cloth dampened with denatured alcohol. Allow to air dry.
3. Scrape any plaque from rollers on the inside of the ball cage and swab them with denatured alcohol. Use compressed air to blow out dust and debris from the interior.
4. Reassemble the mouse.