This seems to be some Vista problem and nothing to do with avast

http://social.technet.microsoft.com/Forums/en-US/itprovistanetworking/thread/563b908c-aa24-4000-9b2d-b6ff02f10c56/

http://www.google.no/search?hl=no&source=hp&q=The+dependency+service+or+group+failed+to+start&aq=f&aqi=g2&aql=&oq=