Best thing you could then would be to contact Nokia and tell them that the device does not work with the touch screen. Be prepaired to wait for a while. Sending mine out to get get fixed because of the white screen of death took 30 minutes on the phone.

If it is new enough (recent purchas) then I'd say take it back to the store.

Re: No response to taps on screen/sem resposta ao toque na tela
 

I have the same problem with my "new" (refurbished) 770. I updated, downgraded, then re-updated the software several times, to no effect. I've posted a question in the Nokia discussion forums - will let you know what I find out.