I totally agree with Keef
Couple of points about Avast though:
first, turn on scanning for PUPS in all scans
next, set the action sequence on detection on the scans to "fix/quarantine/delete" in sequence
If anyone is confused by that, PM me with your e-mail address. I can send you a settings file which will maximise the Avast security settings by turning on the scans and actions......