'404 - Component not found' error in Joomla and Its Solution

Hi Friends,
Some time Joomla shows an error like

'Joomla error 404 - Component not found'

You may not be able to visit this page because of:

1. an out-of-date bookmark/favourite
2. a search engine that has an out-of-date listing for this site
3. a mistyped address
4. you have no access to this page
5. The requested resource was not found.
6. An error has occurred while processing your request.

Please try one of the following pages:

* Home Page

If difficulties persist, please contact the System Administrator of this site.

Component not found

This is due to the problem in Menus System

To solve the problem

1. goto Joomla Admin Area
2. --> Menu
3. Set one menu as Default by clicking the Default button at the top right menu.