Trouble logging on internet with my DSL modem.

I am currently running a fresh copy of Fedora Core 1 Linux.
Everything installed fine and I haven't had any problems running
Linux. I used to use Red Hat 9.0 and I had no problems configuring my
connection to the internet. However, since I have installed a fresh
copy of Fedora I attempted to configure my connection the same as
before. Now I can't seem to get my system to connect to my provider
at all. I have used to configuartion wizard to establish a new xDSL
connection and everything seemed fine (user name, password, etc) but
when ever I connect it claims to have activated my connection yet when
I run Mozzilla or anything else it says that there is no connection.
Can anyone help? I would much appreciate it. This puzzles more since
i didn't have any glitches with Red HAt, by the way, i tried
reinstalling red Hat to make my connection work, but now it too
strangely doesn't want to connect...