k850i touchscreen not working

Please please please !!!
can anybody help, i have a k850i brought it from ebay about 1.5years agofrom hong kong it haddent been released in Australia at the time.
the phones three touch screen buttons stopped working about 8months ago , took it to a tech to get fixed but he replaced the screen and data strap/cable and it still does the same thing , i believe its a program or main running system problem.

is there any way to totally reformat the phone any other ideas would help thanks guys ?:confused:

Same problem on my k850i lcd blank, can i i flashing my k850? Please help me !

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