To avoid poor rankings in search engines, it is important to remove dead links from your web pages. 

Killing those dead links will also please your visitors!

Many web development software packages, such as Microsoft FrontPage, include functionality to find dead links. 

Alternatively, free free tools such as the following ones, can be used: to dentify dead links:

NetMechanic

This site provides free tools to identify dead links.  Their tools also identify spelling errors and slow loading pages.