Apologies to Hero999 it was member 'wraper' that quoted only a portion of my comment.
I'll try to be a bit clearer and hopefully deguass any previous misunderstandings:
The older lite AV program mentioned earlier has not missed a beat for me,
all PCs on my watch have no malware and work like the day they were purchased and software installed,
you would almost believe they were running a lean distro Linux with an eye candy GUI.
When there is no user activity the Task Manager reports CPU usage at 0%, all processors at bottom flatline, memory at startup idle, blah blah.
Any suspect files or attachments scanned have given the same positive or negative results when those same files are compared on other PCs with 'popular' AV program$$$
And as also mentioned earlier, I got off the AV merry go round years ago,
once I realised how the game works
If billions swear by certain AV products, be they free, subscription or trialware, great.
I have better things to blow my time and scarce money on, like stuff that actually works > test gear, tools, good software with author support, bulk discount dunny paper etc
and not horse f@rt around with suspicious hyped betrayware come placebo anti-malware,
smart scripts that embed themselves in Windows and refuse to leave via the normal uninstall methods.
Been there, done that, learnt my lesson REAL GOOD.
Windows 7, Mountain Lion/Mac and Linux are reasonably secure (if you don't fill them with bloatware, crakkks, p0rn toolbars and faux anti-malwares) and good for another 10 years of more imho, and cover most bases.
How much will 10 years of AV expenditure set you back if it's useless?