My Hotpoint aquarius 900 fills with water, and it empties, but won't spin?

My Hotpoint Aquarius 900 will fill with water. the clock
seems to move quite quickly through its cycle, and then empties itself.
I have checked that the drive belt is OK, and the drum will
rotate freely.
Does the clock need replaceing,? If this is the case, A hint of the cost would be nise.

Please could soneone Advise.