Microsoft 免費防毒軟體 Security Essentials

英文版： http://www.microsoft.com/Security_essentials/default.aspx?mkt=en-us#dlbutton

繁中版：
for xp
http://download.microsoft.com/download/3/8/5/385C19C3-1107-4EE5-9C47-D3FAB986B06C/mssefullinstall-x86fre-zh-tw-xp.exe
for Win7 and Vista x86
http://download.microsoft.com/download/3/8/5/385C19C3-1107-4EE5-9C47-D3FAB986B06C/mssefullinstall-x86fre-zh-tw-vista-win7.exe
for Win7 and Vista x64
http://download.microsoft.com/download/3/8/5/385C19C3-1107-4EE5-9C47-D3FAB986B06C/mssefullinstall-amd64fre-zh-tw-vista-win7.exe