Microsoft's free anti-virus software MSE is recommended

Microsoft Security Essentials is a free Microsoft security protection software for certified Windows PCS to help protect you from viruses and malware.

Microsoft Security Essentials can be downloaded directly from the Microsoft website and is easy to install without complicated registration process and personal information. It runs silently in the background and provides real-time protection without disturbing the normal use of the computer. Automatic updates keep your computer protected by the latest security technology, making you feel safer.