How to I restore "Open" or "Save-to-Disk" prompt?

When I receive email messages with attachments (e.g. a Word document), and
when I clicked on them individually to open them, I was always prompted with
a box asking if I wanted to "Open the file" or "Save it to disk". However, I
accidentally checked the little box within that prompt that said something to
the effect of "Do not show this again"...and now I don't know how to get the
prompt to pop back up each time I open an attachment! See, most times I
prefer to "Save to disk" without opening it first...so this prompt box was
ideal! Now, it's gone...when I click on the attachment in my email message,
it automatically opens it

I am currently using Outlook 2002 on Windows XP.