CWmike writes "Microsoft's new free security software, Windows Security Essentials, passed a preliminary antivirus exam with flying colors, said independent and trusted firm AV-Test, which tested Essentials, launched yesterday in beta, on Windows XP, Vista and Windows 7. It put it up against nearly 3,200 common viruses, bot Trojans and worms, said Andreas Marx, one of the firm's managers. The malware was culled from the most recent WildList, a list of threats actually actively attacking computers. 'All files were properly detected and treated by the product,' Marx said in an e-mail. 'That's good, as several other [antivirus] scanners are still not able to detect and kill all of these critters yet.' It also tested well on false positives."