How your browser handles Office attachments depends mainly on your system
settings. Open Windows Explorer and from the Tools menu select Folder Options.
On the File Types tab, locate Microsoft Word Document and choose Edit, as in
the image below.
Notice the four checkboxes at the bottom. Un-check the two on the right and try
your link again.
These settings are more than likely somewhere in the Registry. Where, I do not
If that still doesn't work, try changing the MIME type to be the same as the
one that shows up in the Content Type field of the dialog below: