I've used NAV for around ten years - before Symantec bought it, and it's good. However, Sys Works installs lots of proggies you'll never use, plus it slows the system by about 10% (which they admit). One "Catch 22" to look out for is DL a "freebie" AV and then using a free webscan is that most of them do not scan compressed files - which your DLed AV is.
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