If Excel has already converted your written URL into a hyperlink, you can cancel it by right-clicking on the offending address and selecting Hyperlink, Remove Hyperlink from the menu that pops up.
OR:
Type the url, press Enter key, and then Ctrl + Z. The text will remain but without a hyperlink.
OR:
When Excel automatically creates the hyperlink, click the small star and select 'Stop automatically creating hyperlinks'
