You can not switch frequencies for M760

Dear Sirs,

I M760 VHF radio and are permanently on display only two frequencies. Nothing else can not be set, nor switch. Anyone have a software that I need to load into memory PIC16C74B that the radio was operational again. Or if you have any advice for repair, so I'm very happy. The radio was about 6 months in the service, but I did not fix anything, because it probably can not. I'll be happy for each recommendation.

Stanislav