A hyperlink or link is said to be "broken" when you click on it and instead of taking you to the intended page, you get some kind of error message like "file not found". This happens quite a lot because people and organisations often move or rearrange their whole site. The new address does not correspond with the old address and thus the link is "broken".

If this happens to you, you may still be able to locate the Web page requested, by following these instructions:
Press the Back button which will take you back to the page with the original link.
Determine the Web address of the broken link.
Move your mouse pointer over the broken link (no click necessary), and
the hidden link address will appear in the status/progress bar
of your browser (look for the lower border of the Web browser window).
Go to the home page of the broken link.
The leftmost, very first part of this address will usually be the portion
needed to get to the home page or main site of the organisation. The portion
you need will often end with a suffix such as ".com", ".org",
or ".net" or ".com.au", ".edu.au" etc. In
the image above, the part of the URL that you need is http://www.google.com/.
Write this down to minimise spelling errors, then carefully type it into
your browser's Web site address box near the top of its window,
and press your Return key.