We have a Siemens integrated fridge freezer which is approx 8 years old. Recently it has been making a light buzzing sound and we got up this morning to find the freezer defrosted and the milk in the fridge nice and warm

Any ideas at what may have broke? Can fix it myself if I can fathom whats gone wrong.

Thanks in advance.

have a l;ook here

ukwhitegoods.co.uk