I suspect that Office 2000 is no longer supported and it probably does not play well on Win 7. Make sure Office is updated to the best of your ability (and MS willingness to provide such updates.) I suspect however you will have to consider investing in Office 2010. Office 2000 is probably failing on its default path structure or relying on some Registry configuration which is not present in Win 7.
+1 Zoron. OP Microsoft Office 2000 works flawlessly on Windows 7 including Win 7 64. I have installed Microsoft Office 2000 approximetely 20 times on Windows 7. Be sure and get all the updates from M$.