If you encounter the thing that the Nokia N8 won't charge and worst, if the battery was drained and the N8 shutted down and won't charge or power on, try the following steps.
1. Connect the charger supplied with the N8 to other compatible Nokia phones, like E72 like I did.
2. Wait for the other device (E72) to start charging.
3. After it starts charging, remove the charger from it (E72).
4. Now, try to charge the N8 using the supplied charger that you used with the other device previously (E72).
5. Wait for the N8 to charge or start.
6. DONE!