What upsets me when people don't run anti-virus programs is they are putting OTHERS at risk and they don't care. If a person doesn't care if he/she gets infection on his own machine fine, but the truth of the matter is running a computer without one is a real danger to unsuspecting others and that just isn't fair.

You said on your other thread, and alluded to it here, that you have
4,000 saved emails, and 1,200 sent e-mails
well I am telling you, somewhere in those 4000 save mails are infections and somewhere in those 1200 sent mails are infections which were sent to others. Now if the infections came onto the computer in just the past week or so then only a few of those mails would be infected but with the numbers found I sincerely doubt that would be the case. Plus, you sent infection to others, they send it on to more people and so on.
Many of these infected files were emoticons and it appears they were on emails, so what does that tell you? You had to have passed these onto others. Plus just to make it full circle these same people are emailing you back so they are sending the infections back to you. This is what upsets me because it is 100% needless and 100% preventable and yet you made no effort to do so.

Your one argument against an anti-virus program is that it slows your computer. But the two I have suggested are two of the smallest and least intrusive But most protective anti-virus programs available. I have installed one or the other on many computers and not one of those computers suffered a slow down of the magnitude that you have claimed, if at all. You and I have similar sized hard drives which similar amount of available space, I have used one or the other of these two programs over the past two years and neither one slowed my computer one iota. The only difference I can see between the two computers really is the amount of RAM installed, I have 1.5GB of RAM you have 1/3 of that amount. The would be one reason for your computer being slower than mine, but not by the amount you have stated and not all of the time.
What upset me was going back through your old threads your first thread here you had a computer running THREE anti-virus programs, two of which were Avast and Avira, I got you down to one AND cleaned out major infections very likely due to the fact that you WERE running three at the same time, now on this thread you show you are now not running ANY anti-virus programs.
There just is no excuse good enough for not running an anti-virus program and putting other peoples computers at risk, I am not even counting your own here. Cost? No, the two I gave are FREE and rank extremely high in all tests. Slowness, no the two I gave both are known not to slow a computer. So if your computer is slow then there is another reason.
One is the anti-virus program is not configured correctly, a second reason interaction with unnecessary start ups and you have several. Three, not enough RAM.