No singal on my mobile phone

:help:My phone is Nokia, I don't know is it all right: it always cannot accept any singal, is there any one know why?

Try changing the network settings to manual and scan for the network you are on then log onto it. Also could be your baseband, try turning off 3G and putting it on GSM only with the dualband frequency 900/1800

thanks for your reply.but I do not know how to change the network settings

..or it's blocked by the network.

Check your manual regardings the network settings.