My two cents worth on Avira-
I too was happy with Avira paid (paid has web/mail guard & faster updates), until their updates became slow/iffy & weird errors?
I gave A-Squared free/on-demand a try (#1 97% detection/removal rate!)?-
a-squared Free - Free of charge Anti-Virus, Anti-Trojan, Anti-Spyware, Anti-Dialer and Anti-Worm Software - Freeware!
It found 6 malware that Avira missed (MBAM free found 2 more malware!), and several tracking cookies (a privacy issue with me!).
I liked A2 free so much, that I decided to give A2's full blown 30 day trial a try?-
Pros- With 3.5 million definitions/heuristics, it keeps malware off, and it's fast!
Their Surf/Web guard blocks/rules several bad websites/content... a day! Recommended to activate "Intelligent Alert Reduction"?
Cons- Once in awhile their hourly auto-updates need to be kicked off manually once daily on startup, and then a reboot a few minutes later (also following a virus scan)- same with Avira...
I disable A2 for program installs/updates, or it bombards you with alerts!-
I also pre-submit all downloaded .exe's to Virus Total!
G'day
Scott