Hello Shoeb,
I had my share of fun making PDF opening directly in Adobe Reader without Open/Save prompt - both in IE9 and Firefox ...
Depending on the mode that you want to open the PDF (directly in browser or in Adobe Reader itself) you will need to set the applications correspondingly.
In Adobe Reader you need to set or unset the option "Show PDF in Browser" in section "Internet", depending on what you need.
Furthermore, you need to enable or disable the corresponding add-on/plugin in the browser depending on what you need.
In my scenario I wanted to always open PDF in Adobe Reader - therefore in IE in needed to additionally set the security level of intranet to "Medium-Low" to prevent that Save/Open popup, and in Firefox (Tools-> Options-> Applications) I needed to specify the default program for PDF to be Adobe Reader.
Hope this helps,
Marin
