Dialing/phone number problems

I made the first internet connection on Windows Me after
formatting my pc. Unfortunately I put the wrong telephone
number. Now I'm trying to change the number and I do it
without any problem. But while I dial-up to connect
appears the old number and the connection doesn't work.
I tried as well to create a new connection, I put the
right number and while dilaing, the old/wrong number
appears. I deleted all the connections and made a new
one, but the problem persists.