If you notice a difference between Excel-closed and Excel-open behavior, this often indicates a problem with the settings for that file type in the Windows Registry. You can re-associate and reset the Registry settings for XLS (and other common Excel-handled file types) using the /regserver startup switch as described in this Microsoft support document: MSKB 291288: Description of the startup switches for Excel. Does that help?

Sorry but it doesn't. I don't think the problem is with the way my computer vis a vis my Excel software is set up because all the other browsers continue to work as they always have ---- whatever file is in the link gets opened along with the Excel software.

What do you have in the following list -- mine are all set to "Always Ask":

orange Firefox button or classic Tools menu > Options > Applications

In the search box above the list, type or paste Excel to filter the list.

Do you have any add-ons related to saving or downloading files that might impact .xls files? You can review your add-ons here:

orange Firefox button or classic Tools menu > Add-ons

Check both the Extensions and Plugins categories.

I had looked at both those pages, but obviously not closely enough.

Under Tools>>Options>>Applications>>Excel I showed the options to open directly with "spreadsheet8". I changed that to "always ask". That got around my problem. I had to answer the popup box, but once I did, the file loaded properly.

Under Tool>>>Extentions I found "Adblock Plus" has issued an update around the date my problems started. So I disabled Adblock, and reset the Tools>>Options back to "Open with sheet8" ...

And hurray. Everything works as it should. Thank you for your time and effort.

Sorry, did not say Thank you. Thank you. I appreciate your effort