'404 - Component not found' error in Joomla 1.5

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.

not working in ie8

IE8 is not good at the moment. Many of us are using an alternative such as Firefox , Opera or Google Chrome until IE8 gets sorted.

Or you can enable ie7 compatibility option