Windows XP Support is ending soon! MSE for XP ending too!
Posted by essjae on January 9, 2014
After April 8, 2014, technical assistance for Windows XP will no longer be available, including automatic updates that help protect your PC.
Microsoft will also stop providing Microsoft Security Essentials for download on Windows XP on this date
Update: Microsoft has changed their mind. http://blogs.technet.com/b/mmpc/archive/2014/01/15/microsoft-antimalware-support-for-windows-xp.aspx
Microsoft will continue to provide updates to our antimalware signatures and engine for Windows XP users through July 14, 2015.