Alerter: Most times this service is not used. It takes care of administrative alerts over a network for administrative purposes.

Automatic Updates: Downloading and installing Windows updates. If you think you don’t need this service, you can disable it. Remember that the Windows update website doesn’t work anymore without this service, since the introduction of Windows XP SP2. I advise to keep it unchanged. To work properly, the Automatic Updates service also needs Background Intelligent Transfer Service, Event Log and the Cryptographics Services.