For those with excel 2010 or newer, I found this alternative (to the MSN Stock Quote add-in) ...
http://beforeitsnews.com/financial-markets/2013/03/excel-tip-5-how-to-pull-stock-quotes-into-excel-2010-from-msn-money-2518708.html
Using a built-in Excel function, one can specify a list of stock ticker symbols, and corresponding quotes will be returned (either in an existing worksheet tab, or a separate worksheet tab.
I took the option of having my selected stock quotes appear in a separate worksheet tab. Then, all I had to do is replace the =MSNStockQuote(...) entries (in my main worksheet tab) with corresponding references to the separate worksheet.
I'll have to wait for Monday to see how the quotes are updated (I selected option to have quotes updated in background, and when spreadsheet file is opened.
UPDATE: I copied my spreadsheet (that uses the old MSN Stock Quote add-in) to a computer that is running Windows 7 and Excel 2010, but DOES NOT have the June Windows Updates installed. Same problem occurred (#VALUE returned). So, I do not think that this problem
was caused by anything in the June Windows Update. That leads me to conclude that Microsoft did something on the MSN Money server end (on June 19) to cause this problem.