Was anything detected on the first scan after installation or subsequent scans ?
What is the infected file name, where was it found e.g. (C:\windows\system32\infected-file-name.xxx) ?
Check the avast! Log Viewer (right click the avast 'a' icon), Warning section, this contains information on all avast detections. C:\Program Files\Alwil Software\Avast4\ashLogV.exe
Or the C:\Program Files\Alwil Software\Avast4\DATA\report\aswBoot.txt, open with notepad.
If so what action/s did you choose when they were detected ?
