Are hyperlinks not opening or working in your Excel workbooks? In Excel, hyperlinks are used to open specific documents, files, folders, or web addresses saved on a network server, intranet, or web.

This change can be made via two approaches to changing the default browser – The Microsoft Windows settings pages and your system’s Control Panel. They’re both very easy to follow. Open Windows ...

It's an autocorrect option, you can disable the behavior there. Also, at least in 2000, when you right click on the cell one of the options is "remove hyperlink".