Use Microsoft Security Essentials to guard against viruses, spyware, and other evil software. It provides real-time protection for your home or small business PCs.

Microsoft Security Essentials is free* and we designed it to be simple to install and easy to use. It runs quietly and efficiently in the background so you don't have to worry about interruptions or making updates.

* Your PC must run genuine Windows to install Microsoft Security Essentials. Internet access fees may apply while downloading.