No "Welcome to Setup" screen on boot from CD

You are pressing a key when the "Press any key to boot from CD" message appears, aren't you?

Actually it doesn't prompt me to press a key. It just says "Boot from CD/DVD..."

Even so, I tried pressing keys to see if that would change anything. It didn't.

Sounds like there's something wrong with your CD. A pukka, working XP install CD should give you the message that I mentioned. Assuming the drive reads other CDs OK I'd suspect the CD itself.

I didn't try any other CDs. I did try this CD when I got into Windows itself, and it was fine there. Is there any possibility that it's a BIOS that requires me to hit a key I'm not hitting? I don't get any options like "Hit F8 to do this," there's just a splash screen for P4 with HT that I can't remove.

Doesn't sound like it's the BIOS. I would think the "Boot from CD/DVD..." message is coming from the BIOS, and means that it's trying. If the CD is working (which you indicate that it is) and the CD is a good, genuine Microsoft CD the next thing that you should see is the message (from the boot code on the CD) "Press any key to boot from CD". I guess they put that there so that if you leave the CD in the drive it doesn't automatically start the install again when you reboot.

What you're describing sounds like a CD (the disk itself) that should be bootable but isn't. You might try Microsoft to see if they can supply a replacement at a reasonable cost. I can't see why they shouldn't as you have proof that you have a genuine CD.

Typically the F12 key will get you the boot options and the escape key will get you into the bios at boot up, for changes in the boot sequence. But it sound like your CD may not be bootable. You can if you have a floppy drive and 6 floppy disk copy the boot seqeunce to any of the OS you are trying to use your CD with at Microsoft.com. You may try in the search window for something for example like, "XPBoot Disk", make sure that you copy the correct version as there are several versions of Windows XP for the Home Version to Proffessional, and Proffessional 32bit and Proffessional 64Bit. The Best of luck, I know these things can be a pain in you O&^)&%*)&%*&