Excel hyperlinks

I use excel to list and help manage the various number of projects I am involved with. My PC was rebuilt so that now, when I create an hyperlink to take me from this worksheet to somewhere else it is fine until I save. Then when I click on the hyperlink I get “the address of this site is not valid, etc” message.

I’ve had this problem before but cannot remember the cure: googling it does not help. It was not anything to do with the registery settings.

Paul