Service pack 2 set up dinied!

Hi,
Please make sure you have disabled, or unistalled any antispyware, especially Norton. Disable any antispyware. If you don't have have any antspyware, download Superantispyware here. http://www.superantispyware.com/ Install it, update it, run it, and uninstal it. Go to start>run and type in MSCONFIG. Click on the startup tab, and check the Disable all box. Click done, and reboot. Now try and install SP2.
If you still can't install, check out this link. It requires editing the registry, to be careful.
http://support.moonpoint.com/os/windows/xp/xpsp2-install-problems/

It generally indicates the serial number used for the installation of the original software on your computer has already been activated on another machine.

This is typical of copied software.

As this is an OEM version, Microsoft only allows the software to be installed on a single computer.

Attempts to perform any updates are denied.

If you are the owner of the original XP installation software and have the COA (certificate of authenticity) you can contact Microsoft to allow updates, possibly with the issue of a new key.