what is wrong with my whirlpool fridge freezer?

I have a Whirlpool American fridge freezer, model number S20BRSB21, it is 5 years old. Recently the freezer has been turning off. I am able to press the stanby button on the contrl panel and the freezer turns back on, only to go off again a short time later. I have turned the appliance off for 4 days and then turned it back on, the freezer again worked for a short while, then switched off again. Does anyone have any idea what the problem is?

Gary
June 2010