Save your money on fixing a broken phone rather than investing on a new one. The most common damages that happens to a phone are, cracked screen, speaker, buttons, liquid damage. Screen , speakers and buttons are easily available on internet and mobile store on affordable prices, while for liquid damage take the battery out of the phone, either put the phone open exposed to sunlight or use a hairdryer to dry the moisture from the phone.
No
no
You get a new phone.
take it to a phone fixing store
Replace the wiring that was burnt.
Most of the time the phone company you have the phone through offers a service that fixes your phone. If not nokia has a website and can send you a an address in which to fix your broken phone.
get a new phone
Try taking it to a phone shop, and tell them that you have network problems, but i doubt you can fix it at home :-)
fix it.
tell the phone company and they will fix it
Take it were you got it from and they will replace it or THEY WILL TRY AND FIX IT IF IT IS FIXABLE
Fried Frank has a list of several different contacts that can be reached by both phone and email. A list of contacts can be found at their website.