I'm not particularly computer savvy. I have a Dell Inspiron 15 5000 Series that is about two years old. What's the general feeling on McAfee or Norton antivirus software? Is it mandatory? Optional? I had McAfee for the last year or so but let it expire. Bad move? The computer works okay, but every once in awhile throws a tantrum and takes forever to get onto the interwebs. And by forever, I mean about 7-10 minutes. Should I renew the McAfee? Or deal with the intermittent slowness?