You don't need to dowload it. osa9.exe is the Office Shortcut for MS Office 2000. Simply repairing or reinstalling the program will restore it for you if you've disabled or deleted it.

This article leads to the MS Office 2000 Resource Kit 'readme', which contains all the information you need to know, I think.

http://support.microsoft.com/default...b;EN-US;210875