Multipoint wd440 rinse hold and power lights flashing?

Hi, our washing machine will start to fill and the drum will turn a couple of times and then stop, and the rinse hold and power lights start to flash while it drains the machine. I've had a look at the circuit board, but haven't a clue what I'm looking for or at. Everything looks clean and dry. The belt had come off and I've put that back on again. Could it be as simple as needing a new belt?