While I am not an avid Windows user (I have to use it at work and, occasionally, when I'm at home), I couldn't imagine using it without some sort of antivirus software running. However, I am still surprised at the the number of people who do.
I an remember, several years back, helping one person clean his computer (he had been visiting some pretty sketchy websites looking for music) and he had literally hundreds of pieces of spyware on his PC and several virus and trojans.
More recently, I was trying to help a young woman at church who had let her susbscription to Norton Antivirus lapse. She was online and clicked a button that she shouldn't have and found herself unable to use her laptop.
What I try to share with people is that, in Windows, it is downright dangerous to be online without some sort of antivirus running. Most people reading this would probably say, "why would anyone do this?" What I have seen is a mixture of people who don't know enough about computing to see why virus protection is even important, some who think that they can outsmart virus creators and pride themselves on not using antivirus software and other who simply cannot afford to keep up their antivirus subscriptions.
While I can't do much for the second group but admonish them that they are playing with fire, I can do something for the first and the third groups. For these people, I want to share some free antivirus offerings that should keep them safe in most instances. This is not antivirus with all the bells and whistles but, they should work just fine. In fact, I use free antivirus software on the PC's in my house and don't feel any less protected.
Below is a small list of antivirus programs and where they can be obtained. All are free of charge and provide you with free updates for virus definitions. You will likely have to register and you may get an occassional email from them but, believe me, it's a small price to pay for free virus protection.
Avast! Home (My Favorite): http://www.avast.com/eng/download-avast-home.html
AVG Antivirus: http://free.avg.com/
Avira AntiVir (A CNET Editor's Choice): http://www.free-av.com/
Now, you have no excuse not to have antivirus software on your Windows PC.