Malicious remote control software continues to be one of the biggest threats to Windows PCs, according to a new Microsoft security report.

More than 43,000 new variants of such insidious software were found in the first half of 2006, making them the most active category of malicious software, Microsoft said in a Security Intelligence Report published Monday. In June Microsoft also flagged zombies as the most prevalent threat to Windows PCs...Of 4 million Windows PCs found to be infected with some kind of malicious software in the first half of this year, about 2 million were running malicious remote control software, Microsoft said. The data is collected by Microsoft's free Windows Malicious Software Removal Tool...