Putting electronics in a fridge may work sometimes, but it may also cause irreversible damage if you're unlucky. The biggest threat to electronics is not just temperature but also moisture. Cooling the air captured inside a laptop may cause water to condense on electronic components and may cause subsequent short circuits, which may burn something irreversibly once powered on. Whether it happens depends on the relative humidity of the air you start with and the temperature delta. In dry areas this may be ok, but really don't try that method in tropics (or even in Europe in Summer - I can see condensation happening almost all the time in my fridge).