The power is on but the water won't dispense

Hi, my water dispenser always worked fine until recently. I stopped using it for about 2 years so it was sitting and not being used, though it was plugged in and powered on the whole time. I recently decided to start using it again, but I can't get the water to come out. It did for a day or two after I started using it again but stopped for some reason. I did notice that the reservoir seemed to have an ice "ring" around the inside of it...basically like a block of ice shaped like a donut. I don't know if that's related.