internet hell

[Paul]

i have got a Sony vaio PCG-FR102 that runs on windows
XP. I recently got broadband installed but have only
been able to get onto it once. I initially used a
copperjet modem but Freeserve (despite including it in
their starter pack!) said that its not a good modem. So
I got a US robotics and installed that.
Still I can't connect to the web through broadband - just
the usual phone line dial up. The notebook shows "no
modem" after a few minutes and for those brief few
minutes before the connection to notebook is lost the
modem tells me that it cant connect to the remote
computer.
Can anybody help? I've tried calling all the help lines
that each company supplies but nobody owns up to it being
a problem with their product. Sony say its the ISP, who
say its BT and the phoneline who say its the ISP who say
its the notebook.
I have suspicions its the notebook as another external
device going through the USB is not being picked up by
the notebook.
I'd really appreciate any help. My technical skills are
pretty negligible so need advice
Many thanks
Paul