Any SEO consultant will use Webmaster Tools to check out the current status of a particular website. Sometimes you can see a lot of 404(Not found errors) in Crawl Error pages. So the basic question here is does a 404 Error reported in webmaster Tools can really affect your site ranking. 404s are perfectly the normal part of the web. Internet is such a place that it is constantly changing which means newer and newer content is born each and everyday while old content dies so this is the situation where it returns a 404 HTTP response code.
Search engines are aware of this 404s actually and this kind of errors is preferred by Google. When you get rid of a particular page you must ensure that it returns a proper 404 errors or 410 response codes. For the crawlers to see the HTTP response code of a URL, it must crawl that URL. If the URL is blocked by robot.txt file Google can’t crawl it and see its response code. The fact is that even if you have some URLs that does not exist or return 404s this is not going to effect your site’s other URLs (the ones that return 200)
So if some URLs on your site return 404 can’t hurt your website or count against you in Google search results. But there can be some cases where you get some 404 on pages that you care about this could be because of the misspelling of legitimate URL. So in this case, you can 301 redirect the misspelled URL to the correct URL and capture the intended traffic from that URL.
Our Search engine optimization packages can really help you to attain a higher page rank and better search engine results.