Excel 2003 problem

I have a user that was recently upgraded to Office 2003 from 2000. Everything seemed fine during the install, but I received a call later that Excel was not working (you know how users are). What happens is Excel opens with a blank program window but no spreadsheet. If you click on the open a new document icon it opens the default blank sheet, but it will not open one on its own like it should. I have tried reinstalling Office several times, each time removing more files and settings that are not removed during uninstall, but still the same result. This is not a big problem, except that this user is one of the partners of my firm, and we all know you need to keep the bosses happy. Any help would be greatly appreciated.