The first hurdle was the inability to type in the BIOS password. The only key on the keyboard the system would recognize was "Enter" and it told me that it was the 7th+ wrong attempt and that the system must be shut down. I resolved this by removing the password jumper on the motherboard.
The next problem was a black screen with white letters stating that "\windows\system32\config\system" is missing or corrupt. I have a Windows XP Home Edition install disk. However, when I boot from the disk to use the Windows XP Home Edition Setup, the keyboard no longer works. It is a PS2 keyboard and I've tried 2 different ones. The keyboard works just fine to open the Dell boot menu and choose and confirm to boot from the CD. As it is I cannot attempt to repair or reinstall Windows XP as I can't choose "Enter" "R" or "Esc" without the keyboard.
As an odd and perhaps unrelated note, if I set the boot order to CD first, then hard disk, the system will totally ignore the disk, even if I hit F12 and tell it to use option 3, boot from CD. It will go straight to the missing/corrupt registry error. If I keep the boot order as hard disk then CD, I can use F12 to successfully boot from the CD.
I don't know how to get past this to give this 9 year old his computer back in working order. Can anyone help?