I have winXp SP1 professional CD. i have installed XP Sp1.
Now I have got WinXP SP2 CD. I started setup(i am logged on WinXp SP1
System
as Admin )and selected "Upgrade".
After entering key it goes to next blue screen starting installation.
Setup tells
" Windows has detected that one or more protected core system files
(kernel) on your computer have been modified. The Service Pack contains
updated versions of those files, which work to provide a stable
environment
for your programs. Due to this modification, the Service Pack will not be
installed. For more information, see Knowledge Base article Q327516 at
http://support.microsoft.com. ".

Was the CD you tried to use just the SP2 service pack or the XP
operating system with the SP2 service pack? It sounds like you tried to
use the latter.

You should be able to install the SP2 kit via Windows Update from he
http://go.microsoft.com/?linkid=3646727
or download it from he
http://go.microsoft.com/fwlink/?linkid=23354
and install it later.

Make sure you read this first:
http://www.microsoft.com/windowsxp/s...hattoknow.mspx