doggeral, thanks for your help but you haven’t answered my principal questions yet:

  1. Does the avast! Quick Scanner window always appear or not? I mean, even if you get the ATL Dialog Error box, does the normal Quick Scanner window show up or not (before the ATL Error pops up)??

  2. Does it actually find a virus even if you get the ATL Error box? Try e.g. the Eicar test file (not really a virus) from http://www.eicar.org/download/eicar.com .

Thanks
Vlk