How i can do the factory reset on my Nokia Series 40

Select Menu > Settings > Rest. factory sett. (or Reset device or Restore factory sett. or Rest. fact. sett.).

• To reset only preference , but keep all personal data, such as contacts, messages and media file, select Restore settings only (or Restore sett. only or Settings only).

• To reset all preference settings and delete all settings personal data, select Restore all (or All).
• Enter the security code before the restore. If you have never changed your security code, then enter the default code 12345. If your phone still requests a security code or if you have forgotten it, please bring it to the nearest Nokia Care point for inspection.

How I can reset my Windows Phone 7 to its factory settings

1.	From Start on your Windows Phone, flick left to the App list.
2.	Tap Settings, then tap about.
3.	From the about screen, tap reset your phone, located at the bottom of your screen.
4.	Click yes to confirm your reset.