modem keeps getting error 797

[Ann]

I am constantly getting error 797 whenever I try to
connect to the internet via a dialup modem - it tells me
the device is not installed or is busy. If I reboot the
system sometimes it will work. If I unistall the modem
and reboot sometimes it will work. Once after telling me
I had no device it suddenly started working. Anyone have
any ideas how this problem can be fixed once and for all?

thanks,
Ann