which program hijacks my dial up phone line?

Hi,

I am in a place where there is only dial up. I bought a usb dial up modem because my laptop is mini and has no dial up modem. I am using windows 7.

The modem worked well for a couple of hours but then stopped.

When I try to connect now I get the 'no dial tone' error message. If I connect a phone to the line instead of the modem there is dial tone but if I connect the handset in parralel to the modem there is a noise as if another program took over the line. I moved the USB modem to another laptop with xp and it works well on the same line.

The conclusion is obvious. Some other program is hijacking my line. The question is how to find which one it is so that I can try to disable it? I tried my luck at the event viewer in applications but could not find a solution.

Any help appreciated.

The usb modem is fine because it worked on the other laptop. As to restarting, this was one of the first things I have tried.

thanks. Since its USB it reconfigures itself each time I take the modem in and out a new. So its not that.