I use Avast, too... but yeah, it's not great at all. Slows your system down a lot, lots of false positives, rarely blocks stuff or detects serious threats.
So I turned all the shields off, updates too, made it work in the background... it still slows PC down... only using it for various scans from time to time and reminding me what Software I should update (Flash, 7zip, etc.).
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Malwarebytes Anti-Malware remains the best, especially when combo'd with Adwcleaner, Junkware Removal Tool and Anti-Rootkit Beta.
Norton is an okay one. Kaspersky is pretty good, but it blocks most VPNs though. ESET NOD32 is pretty good too.
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Thanks for the sig Scot-and for the help with my avatar
When someone annoys you, it takes 42 muscles to frown but only 4 to reach out and bchslap them upside down on their head
Full scan (drivers, sectors, system) only takes 1h10min in my case. So it's great whenever I don't have the time to run a full rootkit scan with the standard MBAM.