SG Distributed Computing Teams discussion, S.E.T.I., Folding@Home, as well as other types of cloud/distributed computing, AI, machine learning, cryptocurrency mining.
Simply run adaware, spybot, ZoneAlarm, HijackThis, AVG, update windows daily, have a router, don't open e-mail, turn off action scripting, don't use P2P networks, don't violate EULAs, and wear a condom to get Windows secured.