62% of PCs scanned by Microsoft had at least one trojan

Microsoft scanned the PCs of 5.7 mln consumers and small-business owners who used its free scanning tool from January 2005 through March 2006. It found at least one backdoor Trojan on 62% of those scanned. About 20% of the PCs checked during one period had been cleaned, then re-infected, most often with a different kind of bot.About 35% of the bots were implanted when victims opened attachments sent via e-mail, instant messages or peer-to-peer websites that share data files.