A couple of things i can think of...
Did you old PC die or did the old Hard Disk die? Is it possible to make your old HD the primary HD, or are the OSs different?
Otherwise, how technical are you and how complete is the old disk. Also do you have a Registry backup from the old machine? Office has files in Program files, some in the User's application data and registry settings. it is a tough nut to crack, but it is doable...
Some other programs may be able to be run from the old location it all depepnds on if they put their information in teh registry, or if they stored the License information in the user directory...