How to use Restore CD?

Clarifications

you should be able to boot off of one, it should be labeled Operating System restore or something along those lines, but NOT application restore.
You SHOULD see a little message on the screen that says "press any key to boot from cd" and so tap enter a time or two. Or, your computer may just boot into the OS restore cd.

If that does not work

Watch your computer when it boots up. Just after that single beep on boot up, it should give you some words, they may last onlya few seconds. You may see "Press F12 for boot menu." That is a Dell Default. If you see an "option" for the boot menu, reboot the computer and tap that key, choose cdrom or removable media from the list, this should get you to boot off the restore cd.

And if that does not work...

Watch at boot and look for "Press for Setup."

Reboot and press that key a few times after beep. You should see a blue screen with white text (this is your bios) useing arrow keys, move around until you see boot order or the like, check that cd-rom is listed first. After rebooting, watch for the hit any key to boot from cd rom, its not there long at all.

The XP recovery CDS you just put the first one in and restart the PC. You need your CD to be first in the boot ordr in the bios, and you will need the product key.

The press r hold down F12, stand on your head and blow raspberrirs thing are various methods of getting the manufacturers CD to fire up.
That will wipe the machine to as it was sold, losing everything you've put on since.

If it's vaguely working now , back up as much as you can, note hardware and stuff.