Nokia n70

1.Some operation performed before the phone hang has corrupted your Phone start up data. Thats why your could not able to Boot
2.Remove the Battery or switch on/off one or two times. Check whether Boots this time.
3. Else Remove your Memory card from your phone. also Check Now your Boots up Normally.
4. If phone still persists with same Boot up problem. then one way is to Hard format the phone memory to get back all default settings. So as to make your phone Boot up Normal
5. Hard trick method can erase all your personal information such as Contacts, messages,Wallet data's,Phone Settings.Erase Gallery,Video data.
6.Before you continue this method. Try steps 2 and 3
7. if everything fails and still your phone could not Boot means
8. Press 3 & * & green dial button & switch on/off button Continously until you get Formating Screen.
9.I think your phone boots now. if not Contact service centre. they might flash your Operating system..

thank you