I have performed a full scan using my free edition of avast on my windows xp twice in the last 2 days. Takes forever but it came up with spigot malware both times. It seems avast does not stop them automatically. Why not? What am I doing wrong??
Have you turned on PUP detection?
If you need help, follow instructions here https://forum.avast.com/index.php?topic=194892.0