modem ports

I have installed my modem on nt workstation and it keep default to com2. When I am installing it the only option is com2 mo other ports are there to select. How can I get it to give me the option of selecting ie: com3. The modem won’t dial and itsays it is a port or hardware problem something of that sort. How can i test the modem to see if it will dial.

Thanks,
Jehu.