Sorry - I completely forgot!
When you install from the BT Broadband disc, it installs BT Yahoo Explorer. You don't want to use this and you don't have to (well at least I don't want to and I don't use it).
You don't have to uninstall anything, just open Windows Explorer, go to c:\Program Files\Internet Explorer\iexplore.exe.
right click on the iexplore.exe file and select Send To >Desktop - create shortcut. Then click on that instead.
If I remember correctly, it asked me if I wanted to make it my default browser - answer yes.
Once you are happy that it is working, right click on the BTYahoo icon on the desktop and delete it - you don't need it and it will stop you clicking on it in error. If you also want the Internet Explorer icon on your Quick Launch Toolbar (lower left of the screen), click on the desktop icon and drag it to the quick launch toolbar and let go. It will still leave the icon on the desktop.