I have a 56-K X-2 US Robotics modem that has worked fine for 3-mos. Now when it is connected to the computer all the other phones in the house stay locked-up until they are disconnected and reconnected,even though the modem is not being used. The modem usually works the first time but after the 1st use I get ( Modem bieing used by another dsvice). Has any one had this problem and,or know the solution? Thanks for your help.