Strange problem

On some websites (and there's no rhyme or reason as to which ones), when I click on a picture to enlarge it or take me to another website, or when I click on a link (www.whatever.com, for example), the operation works. The picture enlarges,I go to the website, etc. On other websites, when I click, nothing happens. I can see the new address, for example, in the bottom status bar, but I don't go there, or the picture doesn't enlarge. Any ideas?...In advance, Thanks!

 

Anybody???????