You make think this a bit bullish and contrary, but having inadvertently installed free Norton malware scanners countless times, I tend to treat Norton as malware itself. Unwanted software attached by default to a programme I wish to install is not to be trusted. Along with those unwanted toolbars and browser highjackers, Norton and Macfee invade my system just because I haven't spotted the box to untick.
Instead I use Microsoft Security Essentials running continuously, with Windows own firewall. To back this up I run occasional scans from Spybot and MalwareBytes. In case of infection and hard-to-remove rootkits I hold Spyhunter in reserve; the only utility I pay for.
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