CHAPTER 4: Upgrading Your Computer30Preventing static electricitydischargeThe components inside your computer are extremely sensitiveto static electricity, also known as electrostatic discharge(ESD).Before opening the computer case, follow these guidelines:• Wear a grounding wrist strap (available at mostelectronics stores) and attach it to a bare metal part ofyour computer.• Turn off your computer.• Touch a bare metal surface on the back of the computer.• Unplug the power cord and the modem and networkcables.Before working with computer components, follow theseguidelines:• Avoid static-causing surfaces such as carpeted floors,plastic, and packing foam.• Remove components from their antistatic bags onlywhen you are ready to use them. Do not laycomponents on the outside of antistatic bags becauseonly the inside of the bags provide electrostaticprotection.• Always hold expansion cards by their edges or theirmetal mounting brackets. Avoid touching the edgeconnectors and components on the cards. Never slideexpansion cards or components over any surface.WarningTo avoid exposure to dangerous electrical voltages and moving parts,turn off your computer and unplug the power cord and modem and networkcables before opening the case.To prevent risk of electric shock, do not insert any object into the vent holesof the power supply.CautionESD can permanently damage electrostatic discharge-sensitivecomponents in your computer. Prevent ESD damage by following ESD guidelinesevery time you open the computer case.