Microsoft Security Essentials

Security Essentials is a free Microsoft approach to secure your computer. It protects against viruses and spyware, including Trojans, worms and other malicious software. And surpisingly (for Microsoft) there's no other costs or substriptions.  It's easy to install, usage is also simple, interface is clean and clear. When the computer is clean the Security Essentials icon status is green, when the unwanted software is presented the icon status is red. Security Essentials runs quiet in the background, it doesn't use a lot of system resources, updates are automatic.  I recommend it to al windowsXP, Vista and 7 users. Free download here.