I do not know the % of computers out of 100 are already subject to bot commands.

Sometimes you volunteer your computer to spend time sorting data for SETI or come other research, but bots are uninvited and outside your awareness.

Bots are the tools used by organized crime, Russian mafia extortionists and others.


I do not think there is any protection specific to bots since things like Norton and McAfee are supposed to pick these things up...
but I understand they get through to your computer anyway, mostly hibernate and then spew their venom in unison with other bots.