Hi,
I recommend you to check if the CD you've try to install XP from him – is
originally, and if the product key is compatible to the CD.
Maybe you'll have XP OEM CD but retail product key – so you cannot install
XP until you'll have retail CD.
If you cannot find your original CD I recommend you call to Microsoft and to
explain them your problem (in my case I had only the product key and
Microsoft sent me XP CD only – I live in Israel, maybe in your country
Microsoft's policy is different but it worth a trying).
Good Luck! And feel free to send me questions to my e-mail
([email protected]).