There is only one file type that uses the .XRM-MS extension:
Microsoft Security Certificate
Certificate file created by Microsoft and an Original Equipment Manager (OEM), such as Dell, to digitally verify the purchase and authenticity of software; contains encrypted certificate data signed with Microsoft and OEM keys; used to activate software on individual computers.
XRM-MS files are used when a manufacturer pre-installs software on a computer, such as Microsoft Windows. They typically can be found on the manufacturer's recovery disk.
Updated: November 18, 2009