q series fisher and paykel beeps?

the fisher and paykel q series fridge, the thermostat in the fridge goes bersek, when even sometimes the fridge aint even open that often, the lights flash up and down bothfor the fridge and freezer section, and beeps to let us know there is something wrong der, sometimes you cant even correct the thermostat, to make it cooler again, when its starts flashing all over the place,, so if anyone has had the same problem, i dont even know if you can replace the thermostat, or maybe it needs regasing,,, its about 8 years old now.. thanks for any help...