Well, I poked around a little, turned out there were no extra Excel.xlbs,
but there WAS a second XLSTART folder under Program Files\Microsoft
Office\Office.  There is an add-in there called GWXL97.xla, as well as
PDFMaker.xla.  However, if I clicked Tools and selected Add-Ins, neither of
these appeared.  I do have Acrobat installed and regularly create PDFs from
Excel files.

So... I moved this folder to my desktop, upon which clicking my former
shortcuts to Excel resulted in the msinstaller starting and trying to
"install" Excel from CD.  I made a new shortcut pointing to
C:\Program Files\Microsoft Office\Office\Excel.exe (the old one was
pointing to Microsoft Office 2000 SR-1 Premium, which was grayed out and
therefore could not be changed), opened Excel using the new shortcut, added
a couple of customizations to the menubar, closed Excel, reopened it and
voil…, the customizations are there.  :)   

Anybody know what GWXL97.xla is?  Do I have some weird Excel macro virus or
something? 

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