If a user has the Adobe Reader and plugins installed on their computer, and
clicks on a pdf link, then that pdf document will automatically load in
IE...that's just the way it works. The only alternative is if you right
click, save as, to your computer and then open the file from there. As per
it being blank, that would imply that something is wrong with your PDF file,
or your host perhaps. Maybe review the article about Including External
Files to see if perchance you are writing your links incorrectly?
http://msmvps.com/blogs/dbartosik/articles/category/1922.aspx

Otherwise, post the URL and link of the PDF file you are having problems
with.

DavidF