Actiontec modem dialing & negotiating problem

I have experienced connection problems with my recently acquired refurbished Inspiron 2650 witn an Actiontec modem. The modem operates fine and then after loading windows updates and proprietary software, the modem "hiccups" as it dials a number usually causing a wrong number and if connected to the ISP it fails to negotiate the squelch handshake. I am still trying to identify the software or update that causes the conflict.
Has anyone had similar experiences. Is this modem error prone?