It does, but depending on your settings it may be set to interactive mode were you have to make the decision on what action to take if something is found.
Look in the C:\Documents and Settings\All Users\Application Data\Avast Software\Avast\report\aswBoot.txt file (XP location) C:\ProgramData\Avast Software\Avast\report\aswBoot.txt (Vista, Win7 location), check this file using notepad for info on the scan/detections, etc.