From what you ask, I think the proper questions in this order are:Does the COA sticker tie to language AND type (ex. English XP Pro) If not, then are you using the right CD type for your COA sticker? XP Home CD if your COA sticker is for XP Home - XP Pro CD if your COA sticker is for XP Pro If all three are check, I would checkout the OEMSCAN project found on these forums! Thank you. To make things even worse, because of some shipping problems with the Asus distributor here in Portugal, my computer came with a WinXP Home Simple Chinese sticker, although the system came in Portuguese. And now I don't know how to be sure that the system key matches this Chinese sticker...