I have NIS 2006 on three of mine at home. Not that thrilled with it. I had McAfee until June when the new version refused to work on any of my computers and their tech support was zero help.
Change the world. Of one person. Today.
If your equation requires either a complex combination of variables to get the desired result OR you can't seem to get the result regardless of the variables....it ain't your variables, it's your constant.