This solution can be used or apply to Blackberry series like 8700, 8700c, 8700g, 8700t, 8700v, if found shorted by checking the positive and the negative battery pin terminals.
This problem may occurs if the device is being damaged by a liquid or so called water damaged. In blackberry 8700 series there are two power voltage filter capacitor just located near the SIM card socket, this two capacitors will commonly cause the shorted and failed to power up the device. You can try to remove it first then check if multimeter shows no shorted readings (multimeter range to X1 - deflecting of the pointer approximately down to zero ohms in both by reversing both test probes on the battery terminal)
Then replace it with another one same from other blackberry 8700 series handsets.
