Double check all your cable connections in the home. If your cable wire to the modem connects to a splitter or to a wall connection, replace the cable. IF the cable gets bent, it's ruined. The signal going through the cable is an RF signal, much like the one in your car, and a bent wire can cause the signal to get bounced backwards causing exactly what you have described. ALSO loose connections in the home can allow EMI and RF INTO the wiring, causing the same issue. Verifying all connections are snug, and getting CAPS placed on any wall/cable outlet connections not being used, can in many instances correct the problem, without the need for a technician to come out, and possible a service charge.
