First I assume you aren't using the avast Server Version.
What is the malware name given by avast, the infected file name, where was it found e.g. (malware name, 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.
I'm unsure what you mean by other AVs debugged and got rid of automatically.
But it isn't wise to delete as a first option that is why avast gives options and the best one is to, 'first do no harm' don't delete, send virus to the chest and investigate (as you are doing now).
