Back to Contents PageAdding and Replacing PartsDell Precision™ M90 User's GuideBefore You BeginThis chapter provides procedures for removing and installing the components in your computer. Unless otherwise noted, each procedure assumes that thefollowing conditions exist:l You have performed the steps in Turning Off Your Computer and Before Working Inside Your Computer.l You have read the safety information in your Dell™ Product Information Guide.l A component can be replaced or—if purchased separately—installed by performing the removal procedure in reverse order.Recommended ToolsThe procedures in this document may require the following tools:l Small flat-blade screwdriverl Phillips screwdriverl Small plastic scribel Flash BIOS update program (see the Dell Support website at support.dell.com)Turning Off Your Computer1. Shut down the operating system:Save and close any open files, exit any open programs, click Start® Shut Down® Shut down.The computer turns off after the operating system shutdown process finishes.2. Ensure that the computer and any attached devices are turned off. If your computer and attached devices did not automatically turn off when you shutdown your operating system, press and hold the power button for at least 8–10 seconds until the computer turns off.Before Working Inside Your ComputerUse the following safety guidelines to help protect your computer from potential damage and to help ensure your own personal safety.1. Ensure that the work surface is flat and clean to prevent the computer cover from being scratched.Before You Begin Hinge CoverHard Drive KeyboardMemory Coin-Cell BatteryModem Optical DriveMini-Card Internal Card With Bluetooth® Wireless TechnologyNOTICE: To avoid losing data, save and close any open files and exit any open programs before you turn off your computer.CAUTION: Before you begin any of the procedures in this section, follow the safety instructions in the Product Information Guide.CAUTION: Handle components and cards with care. Do not touch the components or contacts on a card. Hold a card by its edges or by its metalmounting bracket. Hold a component such as a processor by its edges, not by its pins.NOTICE: Damage due to servicing that is not authorized by Dell is not covered by your warranty.NOTICE: When you disconnect a cable, pull on its connector or on its strain-relief loop, not on the cable itself. Some cables have a connector withlocking tabs; if you are disconnecting this type of cable, press in on the locking tabs before you disconnect the cable. As you pull connectors apart, keepthem evenly aligned to avoid bending any connector pins. Also, before you connect a cable, ensure that both connectors are correctly oriented andaligned.NOTICE: To avoid electrostatic discharge, ground yourself by using a wrist grounding strap or by periodically touching an unpainted metal surface (suchas a connector on the back of the computer).NOTICE: To avoid damaging the computer, perform the following steps before you begin working inside the computer.