Prohibited file type in Mail

I occasionally receive email attachments with a .doc extension that Windows Live Mail considers to be dangerous and has, therefore, deactivated. I recognise I can free the attachment by dragging it to the desktop or going to Home>Junk>Safety Options...>Security in Windows Live Mail and unchecking the box adjacent to 'Do not allow attachments that could potentially be a virus to be saved or opened'. However, in whatever application I try to open the file, nothing meaningful appears - it comprises hieroglyphics. Can anyone throw light on this matter?

.doc are Microsoft Word documents. This is part of Microsoft Office. Do you have this installed?