Microsoft has now released the update for its anti-virus and anti-malware software Security Essentials 2.1 for Windows 7, Vista and Windows XP users, you van download it now at Download Center in 32 bit and 64 versions.
Remark : Microsoftdoes not have any separate edition of Security Essentials for Windows XP like its predecessor, so the same download file which is available below for Windows 7 and Vista is compatible for Windows XP systems as well.
More details about Microsoft Security Essentials updates please check Microsoft Support.