Antivirus programs are next to useless and catch almost nothing but stuff that floated around years ago. Its insanely easy to defeat antivirus, despite whatever "heuristics" they market to you.
This is how you secure Windows on a home machine:
Install EMET
Run as a non-privileged (non-Administrator) user
Use User Account Control
Don't install things that you download from random places.
Disable things like Java that you do not need
Keep Flash up to date
Don't open suspicious documents
Use Chrome or Firefox with no-script
You are now impervious to 99% of common malware.
This is how you secure Windows on a home machine:
Install EMET
Run as a non-privileged (non-Administrator) user
Use User Account Control
Don't install things that you download from random places.
Disable things like Java that you do not need
Keep Flash up to date
Don't open suspicious documents
Use Chrome or Firefox with no-script
You are now impervious to 99% of common malware.