If your operating doesn't include a policy editor (Windows XP Home, Windows Vista Home), edit the Registry directly. Just create the following key:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Update

and add two DWORD values:

AutoUpdateCheckPeriodMinutes - auto-update check interval (for example: 1440 to check for updates once a day)

DisableAutoUpdateChecksCheckboxValue - 1, if you want to disable the auto-updater; 0, if you want to enable it.