How do I fix my GW608 washing machine?

Part way thru the cycle, both the hot and cold lights flash together and the machine beeps when the machine has been selecte to run on a cold wash only. The filling speed also seems to be very slow. Then the machine stops and does nothing further. If you reselect cold water, it seems to fill again and then stops again, then washes and stops and then keeps stopping with the hot an cold water lights flashing togther. And so the "cycle" repeats. What can I do to fix it?

Thanks Wayne H