Local file hyperlinks opening in IE
 

I have a set of hyperlinks in a worksheet that look like this
...\..\SUNDRY\CD+DVD\CD-DVD Inserts\Quiz2006\Quiz-2006-TV.jpg

When I click one of these it normally opens in IrfanView, which is
associated with JPG files (I've checked and that is still OK). But
today it has started opening in IE7! That's not even my default
browser (which is Firefox).

Anyone have any idea what's happening here please?

--
Terry, East Grinstead, UK