trouble with key code

If it is a new windows disk and you can not enter the key code correctly, contact Microsoft. Of course you are entering the key code from the Microsoft Windows disc that you have, not the COA of the computer. The product Keys are bound to the specific type and language of the CD license with which they are purchased. A WinXP Home OEM Product Key won't work for any retail version of WinXP Home, or for any version of WinXP Pro, and vice versa. An OEM Product Key will not work to install a retail product. So you must use the key code that came with your CD. Hope this helps, good luck.