As always, back up personal data

You should not use the "three finger" reset!

Instead do this:
1.Press down the power button for 8 seconds.
2.Restore the factory settings by selecting Menu > Settings > Phone > Phone management > Factory settings > Restore.

Code:

Source:http://discussions.europe.nokia.com/t5/Nseries-and-Symbian-Smartphones/How-To-Hard-Reset-N8/td-p/772128