Best free antivirus:
- Avira free
- BitDefender free
Avira works best on my AMD W8.1 system whereas BD free works best on my Intel W8.1 system.
Best free complete internet security suite:
CIS works well on both my systems.
My suggestions are based upon my own experiences using the actual programs recommended. These have proven to provide a solid, respectable baseline security with the least amount of problems, quirks or issues.
Really, when it comes to a complete freeware internet security suite that includes a firewall, there really are no alternatives to Comodo - except perhaps Fortinet's FortiClient. FortiClient has had a mixed review history and I do not know anyone who uses it.
NOTE:
Follow the guides here at MT on how to configure Comodo - otherwise you might think it is messing up your system when, in fact, it is working as intended. It takes some time and effort - and a high frustration tolerance - to get used to. Once you learn how to use it, it is quite capable.
Qihoo is worth looking into as well... but honestly, I've never bothered with it - so I can't comment on it - let alone recommend it. Others that have used it hold it in high regard.