If you have turned off the Automatic Updates service, installing Windows 2000 SP4 may turn it back on.
If you had turned off the Automatic Updates service by setting the startup type to Disabled in the Control Panel / Services, this issue will occur.
To fix this problem, use the Automatic Updates applet in Control Panel to clear the Keep my computer up to date box. Press Apply and OK.
NOTE: If items in the Automatic Updates dialog are dimmed, see 5809 » How do I configure Automatic Updates by using Group Policy or the registry?