McAffee antivirus letting a lot of junk through?

I have always had McAfee on my PC, never liked Norton, don't know why, it just seems to hog so much space and the files, which I guess it needs to do, but even though McAfee always worked in the past, the last 1 1/2 years it's letting junk through constantly. I have to be wary of every freaking link I open for fear of getting one of those fake virus scanning things, my husband pc crashed twice and needed to be reset at factory settings. I'm at the point I'm beginning to wonder if Mcafee isn't doing this on purpose to try and get you to purchase their virus removal for 89.95? Am I being cynical? Any suggestions? I'm familiar with other products but am wondering if Windows 7 is sufficient for basic pc stuff including Facebook and Twitter and web searches. FYI - I don't do anything funky like hit sites that are nortorious for viruses and spyware but I do shop online. HELP!!!! If Windows is good enough I don't want to spend the money on additional stuff...