Since we are mentioning brand names, I like the pro version of MBAM, which BTW has recently hardened its code to avoid manipulation by the malware. Avast will report it as a root-kit on the XP platform(false positive). For my rather indigent clients, I like to pile on the anti-malware, and pick them by their various technologies - this way whatever kind of passive or active real time protection does not conflict.
With the right tools - a scan of the hard drive will not result in any secure data being detected by the crooks. My honey pot tests confirm this.
I got to admit though - even though I dropped Lavasoft's AdAware, I have noticed some malware manipulations on limited rights accounts, that can still be vexing and lead to eventual compromise on a novice's machine. My clients who do not bank or shop online still use it; but you have to cow-tow to their AV, as it is a suite product now. It is still free; but it must be conflicting with some of my kernel based solutions, and I can't get any stability out of it(as if I trusted them anymore anyway).
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