First, what caused the home page to change? It could of been Comet Cursor, Gator or any other programs which could be spyware. Sometimes websites change the internet explorer homepage because you've accessed them.
Ntl could of changed the home page for you.
You said that you changed the home page to the default. The default could of "CHANGED!".
To help solve the problem ,beast, you need to post a response to this subject about what caused the homepage to change.