Removal of Dead Links on a Web Site using Webmasters tools

"404 Not Found"

"Error 404"
 

"The requested URL [URL] was not found on this server."
 

"HTTP 404"
 

"Error 404 Not Found"
 

"404 File or Directory Not Found"
 

"HTTP 404 Not Found"
 

"404 Page Not Found"

One of most serious problems plaguing the World Wide Web (WWW)
today is that of broken hypertext links, which are a major annoyance to
browsing user.
The root of the problemlies in the current Web architecture’s lack of support for referential
integrity
If you delete a web page of information on your site or rename a whole site it will take a long time before the WebBots that index all the information on the WWW get round to cleaning up the 404 Errors.
You can speed up the process on Google by requesting the pages be removed from the search engine.

http://www.google.com/webmasters/

Sign in to Webmasters Tools
Enter your Gmail address and Password and log in
Enter the URLyou want removing for the web page
It will confirm it is not linked and then add to the pending removal list.
Check after 90 days to see if it has gone,