Yeah, every time I've seen Mcafee antivirus, not too impressed. Don't really like norton either, though I've heard it's better this year.
But I use AVG free edition, and also I use PC tools firewall plus. Plus I have steam installed and so far no major issues.
As far as removing norton, try using a program called revo uninstaller, it may be able to help you out, it uninstalls the program and then scans for leftovers and removes those as well.