Step1
Step one, do not turn on your phone.
Step2
Pull off the back cover of the phone, and remove the battery.
Step3
Set the battery aside, and put the phone in the oven or toaster oven without the battery.
Step4
Bake the phone at the lowest setting the oven has. If the oven has a "warm" setting, this works the best.
Step5
Let the phone bake for about eight hours before removing the phone from the oven. Let the phone cool completely, and re-insert the battery.
Step6
Plug the phone into the charger and let it charge. Then try turning it on, and it should work again.