Vic is right...also the 1st thing i'd test is that the connection is fine and that you do have a valid internet connection, try and get to http://www.howtomendit.com or http://www.google.com
This will prove your connection, after that it must be that your original home page is no longer valid, has changed address or is no longer in business! ;o)
Becks
March 2010
Internet Explorer is not a Home Page, it is a browser provided by Microsoft and so you question doesn't really make much sense.
A 404 means that a page does not exist on the server that you are accessing. (Nothing to do with your PC as such.)
Perhaps if you post new question with the URL that is failing or what you want as your Home Page, someone may be able to help.