cyrnel

"net stop wuauserv" doesn't change the startup type which for Automatic updates is normally set to "automatic". Open services.msc and change it to manual or disabled.

XP Home? gpedit.msc isn't part of XP Home edition. (There's more to it than just adding the file.)

Automatic updates options can be greyed out for several reasons. You aren't admin, you're part of a domain and policy prevents it, or something has added registry entries that simulate the policy situation. I'm not sure why but that last one seems to have happened to many people in the last month.

Stopping the service will do, but look for this registry entry:
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\...
...WindowsUpdate\DisableWindowsUpdateAccess

If it's there, delete it. Now check the control panel again.

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There are a vast number of people who are uninformed and heavily propagandized, but fundamentally decent. The propaganda that inundates them is effective when unchallenged, but much of it goes only skin deep. If they can be brought to raise questions and apply their decent instincts and basic intelligence, many people quickly escape the confines of the doctrinal system and are willing to do something to help others who are really suffering and oppressed." -Manufacturing Consent: Noam Chomsky and the Media, p. 195