Using nokia c6 pin code on the handset is yet other rare but essential requirement of a c6 user willing to unlock or lock.
nokia c6 pin code is often helpful when dealing with keyboard shortcuts, or when unlocking the phone from its network restrictions.
Before you could really do a hard rest to your phone, make sure to get into the settings in the Menu, where you would find an option as Factory settings under phone management.
Ensure that you read the OVI booklet that came with the handset, in order to know the service provider preferences.
The handset however, seems to be the interest that the service providers have stacked to, so nokia c6 pin code usage have been becoming much more difficult.