Don't understand these virus et al packages like McAfee that you have to pay for. I used them in the past when running Windows OS machines...they were all intrusive, invasive and cost money.
The last three years of Windows OS machines I ran Microsoft Security Essentials
...costs nothing to download, provides all the protection I ever needed, is written by Microsoft for Windows OS machines, is updated daily as far as I could make out, wasn't invasive or intrusive and never gave a me a moments grief. Just like owning a Mac, in fact