Maybe update drivers?
Try a different modem?
Is the modem in your friend's laptop built in or can you take it out? If so, try putting it into your laptop and see if you still have the problem.
Try totally uninstalling all internet related software (AOL, IE5, modem etc), run error and virus checkers, defrag your laptop and then reinstall all software.
I think that defragging could be a good option because my computer at work was running really shitty. When I launched IE5, it just froze (this was before I even got on the internet). Once I defragged it, it was fine. (My work was using NT4 but its still worth trying).
If I think of anything else, I'll post it.