Normally, the installation program will not update Windows XP Operating System pre-installed on your machine if the language of both versions are different, or if you are using an installation disk that contains a full version of Windows XP
In this case insert the installation CD-ROM and run the program "winnt32.exe." We will ensure that the installation directory is the same as the directory of the version of Windows you want to update. Continue the installation until we have to reboot the machine, when you press ESC to do it manually and return to the Windows interface. In the root directory of the boot partition (usually C:), find the $ WIN_NT.BT $, which contains a file "winnt.sif" which will open in Notepad (notepad.exe). They locate the string "winntupgrade = no" and change the value "yes". Save the file, reboot and continue with the installation as normal, to be completed by performing a system update installed.