Wiondows registry - where is the default browser setting stored?

[speckytecky]

Having downloaded the CEOP browser on three of our workstations to find that it kills our default homepage from the Cache I want to remove the CEOP browser and revert it to the usual IE8 (tried deleting the CEOP Browser and reinstalling IE8 - but the CEOP browser persists) picking up the school Espresso homepage as the default.

 

I'm pretty sure it will be a Registry edit thing but for the life of me I can't find where - HKEY-USERS etc / Microsoft / Software / Internet Explorer brings up a value not set.