Firstly, Avast is not hard to uninstall. Sometimes with any program, some files do not come out cleanly with the uninstall program.
Avclear (for version 3) or Avclear4 (for version 4) can be downloaded from Alwil Trade Ltd. (
www.alwil.com) Avclear does exactly what it says....clears all of the leftover files of Avast.
Normally, with an upgrade, I would say that you could leave Avast Home installed since Avast Home and Pro share many of the same features and engine.........
however, to be sure of a clean install, I would remove Avast Home, use Avclear4 and then install the Pro version.
Good luck
