Modem Can Longer Conect


please help, I need the net for my livlihood. I was using netzero, I got a 'software corrupted' error message, re-started computer then id/login not recognized. Now I get 'modem can't find carrier signal" message. I have messed with the modem/network/ppp, settings as netzero techs have suggested and nothing works. It just keeps disconnecting. Tried an AOL disc, same problem.How could I just lose my modem like that and what can I do about it? thanks in advance.

I have Emac10.1.5