Microsoft Security Essentials / Windows Defender (The 2 are the same.. one goes to Windows 8, the other Windows 7.. something like that)
These are my protectors.. I don't have anything else but Windows Defender and I've been Virus free all year I've had this computer. Well, a year of this computer will be December 31st.

I also do a Full Scan every night for infections, viruses, etc. every night before I go to bed, using Windows Defender...
I'd suggest you to check out Windows Defender/Microsoft Security Essentials, and take Avast off.