One of the things I dislike about Microsoft Office and Internet Explorer, is when people upload and post Office documents to the web and then when I come to click on it, rather than offer me the option to open or save the Office document, Internet Explorer opens the document in the browser window.
Now for viewing documents, this generally isn’t too much of an issue, however for printing, changing and saving the document, well totally different story.
It’s one of the reasons I prefer using Firefox and Mac OS X.
However if you have “accidently” configured your system to do this, it is possible to change it back.