Ok if the dishwasher is pumping all the time then what you will find is there will be water in the bottom of the base of the dishwasher which has activated the flood switch. If you say you had a problem with the sink then this will have caused the water to leak into the base and cause this fault.
All you need to do to fix this is pull the dishwasher out and tip it 45 degs backwards. This will allow the water in the base to drain out so you will need a towel for that part. Once the water is out the anti flood switch in the base will reset itself and allow the dishwasher to fill with water and wash again.
If you need anymore info just get back to me.