When you first turn your computer on (before windows starts) you will see a message that says to press a certain key to enter setup. it's usually an F key or esc or del. Pay attention, as this message may flash very quickly. Repeatedly tap that key to enter setup before windows starts to load. This will take you into your BIOS setup.
In BIOS you want to look for boot order or boot sequence or boot priority. You want to set your CD drive as the first boot device. You need to move it up to the top of the boot order.
Once you have your CD drive set as the first boot device, insert your XP CD into the drive. Now exit BIOS and SAVE CHANGES (F10).
Your computer will restart. When it restarts you may see a message that says "press any key to boot to CD". I've never been able to find the "any" key so I just usually tap the space bar - it seems to work okay. Once you've done that, you should hear the CD start spinning in the drive and see a blue screen with "windows setup" at the top. It will load a bunch of files and then you will see a screen that says Welcome to setup.
At that screen press R to enter the recovery console. The Recovery Console will start and ask you which Windows installation you would like to log on to. If you only have one installation, press 1 and then press enter. Then you'll be asked for the password. If you have no password on that computer just leave it blank and press enter.
You should now see a C:\Windows> prompt.
At that prompt type expand E:\I386\explorer.ex_ %systemroot%\explorer.exe and press enter. This command assumes that your CD drive's letter is E. If your CD drive has a different letter substitute that letter into the command after the word expand.
