Computer virus

Why are there people out there that feel the need to ruin others computers? I will never understand it. I guess it keeps those virus protection makers in business.
The really horrible thing is I have virus protection on my computer and it isn't really protecting my computer. My virus protection is up to date, and hasn't prevented me from getting slammed by a virus.
Today yet again I got something that popped up about Anti-Virus 2009. Anti-Virus 2009 is a fake virus program that can destroy your computer if it gets downloaded. It can also scam you out of money. I am not a computer genies, but I know a thing or two about computers so I knew the first time I had Anti-virus 2008 on my computer. It was a fake spy ware virus that messed up my computer. I still don't have access to my screen saver or background image.
When I saw this pop-up on my computer for the Anti-Virus 2009 I didn't acknowledge it at all like the computer guy told me. I was told that just by clicking on it, the virus could download. So I disconnected from the internet, and restarted the computer. I'm not sure if it was the smartest move or what. Honestly I didn't know what to do. So far I don't have any signs of this stupid virus on my computer, so thats good. But the sad thing really is that my virus protection isn't alerting me of this crap!