System is winserver2003 sp2 recently appeared a problem is the World Wide Web Publishing service always stop yourself,

Then I release all sites are stopped, and then I just manually start one of the sites, the service was launched, and then a period of time the service stopped, at first, the service every 20 minutes to stop once, for a second, and then stopped a period, sometimes interval for a few minutes, sometimes interval of half an hour, not necessarily, how to return a responsibility excuse me, how should I solve it