I have used so many things like url removal request and deleted the pages etc., but still the errors are shown in my webmaster tools.
How can I remove the urls completely from Google?
You can: Remove a page or site from Google's search results, but it will take a while before it takes affect.
The short answer in the context of being practical: you can't.
What you can do is remove links that point to them and make sure that the pages respond with a 404 status code, and when Google sees that the pages are no longer in existence they'll eventually purge them from results.
In general, you can't. But there are some options.
One option is to remove the pages from your server entirely, and make sure they respond with 404 errors.
Another is to use the
A final option is to use the
For details, see Google's page on this topic: http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=164734
There are two way to Remove URLs from Google Search Engine
If you don't want crawl your page in google, so you have to use google webmaster tool's Removal URL tool to request its removal Here it is the way
after few day your url will be delet from search engine and not able to crawl.
If your site has content you don't want Google or other search engines to access, use a robots.txt and disallow the folder of that web page.
you can use one of the above step to Remove URLs from Google Search Engine