I found this interesting
http://www.avira.com/it/company_news/drive-by-downloads.htmlAvira survey: only one out of every two people know the danger of Drive-by-DownloadsTue, 19 August 2008
Using alleged harmless websites, offenders smuggle malware, such as viruses, Trojan Horses and Adware, unnoticed on to computers. However more than half of the internet users have never heard of Drive-by-Downloads.
Tettnang, 19 August 2008 ? Phishing, Pharming, Spoofing and Drive-by-Downloads: the possibilities for money-grabbing online scams to spy on personal surfing data are increasing. Eleven percent of users underestimate the danger of falling for online scams because "they do not visit any obscene internet pages". This is a big mistake as it only needs the user to surf on an alleged harmless internet site, the opening of an e-mail or just clicking of a popup in order to infect the computer with dangerous malware. In their most recent survey, the protection experts from Avira have posed the "moral issue of the month" to 10,390 visitors on www.free-av.de: "In all honesty, are you really aware of the risk of Drive-by-Downloads?"
I use Avira on my old 500MHZ PIII 512MB RAM system running XP Pro SP3 and it works quite well.