SB, this link will take you to the Microsoft Download Site Main Page.
<a href="http://www.microsoft.com/downloads/search.asp?" target="_blank">http://www.microsoft.com/downloads/search.asp?</a>
At first sight there isn't much there, but when you click on the little red cross labelled "next 40" you will find the update/upgrade patches for all MS Windows and Applications including Office.
You can, of course, restore originals from the Windows installation disk, but these upgrade downloads will often contain more recent versions.