If it is a 404 page, do not assume that it's something the user has done intentionally. Links change, sites link wrongly. Link-shit happens.
If you really want your users to be helped by your site, even when they've ended up somewhere they probably shouldn't have gone, you need to have a basic 404 error page which gently describes that the page doesn't exist and contains a link back to the home. Not everyone using a website will see "404" and understand what it is, and without a link back to the main site, a user (potential customer) is lost.
If you really want your users to be helped by your site, even when they've ended up somewhere they probably shouldn't have gone, you need to have a basic 404 error page which gently describes that the page doesn't exist and contains a link back to the home. Not everyone using a website will see "404" and understand what it is, and without a link back to the main site, a user (potential customer) is lost.