Open browse window to a specific folder

In using Acorbat Pro v8, I'm trying to add a button to my form that opens the browser window to a specific folder on my computer and then insert the selected pdf file after page 2 of the form. I've tried several things but none of them seem to work. I'm somewhat familiar with JavaScript and the guides, but have not been able to find any useable code.

Along with that I'm also trying to add a button that will do the same thing, but automatically select the latest document in the specified folder and instert it into the form. This may be asking too much.

Please help.