Pro tip: I use Windows Defender and this rarely found, nearly-impossible-to-get program called common sense. I've been using computers for close to 15 years now and I'm proud to say I've never yet been the cause for malware on a computer. I manage my family computer access carefully and we're doing quite fine without any 3rd party program (2 desktops running XP, 7 and 8, 3 laptops running 7, 8 and Ubuntu). I used Kaspersky on Win 7 earlier. It was the worst hog I ever saw, and I replaced it with MSE. The one time I had to resort to MalwareBytes was when someone turned off automatic updates on one laptop, letting in the Blaster worm. A wipe and clean install later, all was good. I keep a lot of cracks and keygens (yes, stop judging me, you rich kid!) and I don't like AVs that delete/quarantine them repeatedly. I know what I'm putting into my system, dear Ms Ann T. Vyrus, thank you very much. You want an AV no matter what? Go in for either a free full-featured one (that doesn't nag you to buy) or buy a paid product. Cracks and workarounds will probably negate the effect of an antivirus entirely.
I confirm that Symantec endpoint is really a good product. I wait version 12 RU4 that will be compatible with win 8.1