Sorry if my english is not good. I need install Windows Xp Pro (2002) on an external USB drive on a HP laptop,because I have a lot of old soft inoperand with Vista. Computer product name : HP Pavilion dv7 Notebook PC, serial number : CNF92331ZC, product number : VE139EA#ABF, MB : 3624, CPU : INTEL CORE 2 DUO P7350@2Gh, Mémory : 4096ko, BIOS Version : F12. I have carefully pass the steps of an Nlite CD, all drivers seems to be on the disk, the XP setup begins, but the system installation asserts that the CD is not a microsoft original product. The Ms CD is rejected for the same reasons. Or this MS CD has been used for years on an old Toshiba laptop who burned this summer. Where is my mistake ??