One of the most common reasons for getting a "404 - Component not found" error on your Joomla 1.5 front page is a missing default menu item.

To resolve the issue, make sure you set a default menu from your Joomla admin area > Menus. Choose a menu item and set it as default by clicking the Default button at the top right menu.

In our Joomla 1.5 tutorial you can find more information on how to manage your Joomla application.

If you have problems resolving the issue yourself, ask your host for assistance. SiteGround provides the best Joomla hosting and such requests are handled with ease.