Screenshots here, get your screenshots..
It really is quite simple, firstly though, I highly recommend against the BT Internet software, although you may have to use it as a last restort.
You will need your username and password
To get to DUN (Dial up Networking) go to my computer then DUN. right... once there you should have somthing like this;
That is your BTInternet account. If you click on the Create new Connection icon, you will get a dialog like this. its pretty self explanatory really, just put in your details, and select your modem from the list (if you have any choice)
once you have done that, you will be taken back to picture #2, if you right click on the connection, you can put in the dial up number which is "0808 9933001" which is different to the one i last told you!! but anyway.
now go to Server Types, and windows will automatically have a whole bunch of things selected which is bad, so you need so UNtick them here. \/
Once you have done that you need to enter your username (should be
somthing@btinternet.com) and your password
click save password, and you're done! now just use this connection to connect to the internet whenever you need it
hmm sorry i couldn't do it any clearer, i didn't have enough time. good luck though