inoperative links

I am running under win 98 se and use explorer and use microsoft outlook express for my email. I used to be able to click on a link embedded in my email and go to the site. Now when I click on a link, it does nothing. I don’t know what changed, I now have to copy the link and then past it into the explorer address bar to get to the site. Any help in restoring the ability to click and go would be greatly appreciated