Alright Gentlemen I am here to help you finding your RIGHT DEMO like a Boss.
First: Accept me as your savior or this won't work for you :D.
Alright let's go.
1- Download mw3demoinfor (it's not a virus,trust me I am an Engineer):
http://www.mediafire.com/file/hv99ocj9bb5ak63/mw3demoinfo.exe
or...