please help windows defender installation

[xkorinnax]

when i try to install windows defender it says : windows cannot open this
file windowsdefender.msi....please choose a program from the list. I kno
my inst a ller is installed properly....please...helo

 

[Dave M]

It's probably not the installer itself, but rather the file associations
that are out of sync. If you're on XP, try going here and re-associate the
..MSI file extension:

http://www.dougknox.com/xp/file_assoc.htm