I haven't used an antivirus programme for 7 years, running win xp on the pc and win 7 on the laptop.
I have malwarebytes on pc but haven't scanned for 18m, ran it on lappy 12m back an it found one or two ropey looking entries, other than that, I'm clean.
Been around the internet for 20 years, can tell when there's an infection and I've not got infected in all the time I've been without antivirus.
how do i know there's not thousands of infections lurking in both machines? - I do an online scan every few months, never found a thing
I use ccleaner, but this is just a maintenance tool, deletes all the accumulated crud but it's a good way of removing programmes and cleaning the registry too