Well it should be apparent the this person has found some way to connect?? Does the modem do anything? Do you not have a modem diagnostics tool? There should be one in the System Information under Network diagnostics. Should tell you something under Modems? I had a similar problem with my 3com card but it worked in DOS. Had to do a "Clean install", but I don't recommend that unless you have tried EVERYTHING else first.
Agree with brant...If the guy is posting a message my guess is he can download a file.
What do you mean you cant connect after reinstalling me? After a clean install you will need to configure your connection again. If you have done this but still cant connect what error do you receive?
Include your system specs/isp&connection type and any software your using to connect such as the AOL browser.