Roger,
First, check your phone lines. The house (or premises) wiring can often be the culprit. The line from the pole to the house typically terminates at what's called the "Customer Interface Box", the little grey (gray?) box outdoors on the wall. The line that runs from the customer interface box to the wall jack, in the house, into which you plug your modem phone wire, should BE A DIRECT LINE WITH NO BRANCHES AND NO OTHER PHONES ON IT!!!.
Also, if you have a bunch of unused phone wire in your house disconnect it.
This has solved the problem for a few of my friends, especially those who use dial-up and live more than 3 miles from the Central Office. The longer the subscriber loop (in miles) the more sensitive the phone line is to extra loading from wires(and the slower your connection speed when you log in to your ISP).[This message was edited by Ray Minich on 13 May 2004 at 01:54 PM.]