Uhhhmmm - I've seen utilities that will identify it for you - it follows each thread back to whatever called it, and identifies dependancies, etc. But, you can check something real quick before going to a lot of trouble. Go into services, stop and disable the DNS client. It's unnecessary, and everytime I've seen this problem, disabling that DNS client solved the problem. Your mileage may vary, but it only takes a minute to stop the client running.
Quick answer done - it would be good to know what operating system you are running.
This should give you a handle on what's going on:
http://www.neuber.com/taskmanager/index.htmlGood luck!