My son gave up cable Hi Speed Internet from his pc.Now when he tries to use a dial up internet server,msn,he gets a pop up that reads " modem not connected".It is w/ me.It wont check to see if there is a dial tone or anything ,it just says to trouble shoot cuz modem not detected. When cable internet hooked him up,did they do something to his pc that needs to be redone back?..............help!