Any help please on why I'm getting a 633 error [modem in use by another program] whenever I try to connect to my ISP [Netzero].  This happened on Friday and I canNOT seem to resolve it.  I have about $50 in service calls to Netzero & no resolve.  I've rebooted, unplugged, uninstalled Netzero & reinstalled. I've tried to minimize everything in the task manager to the point of system shutdown. I can use the same phone jack to access the ISP with my laptop [no problem].  I do not have any other devices installed like Palm pilot or anything that might try to use the modem. I use Norton anti-virus and there is supposed to be a firewall in existence on the modem. THANK YOU if you can give me a clue.