If your unit starts rebooting randomly, this is a result of a battery that shorted out.
In both cases the simple solution is to buy a new rechargable battery.
You need a special kind for the VoicePro, and your can order it from Amazon, just click here.
We found a battery with the same specifications and half the price. Ironically, it's sold as a replacement battery for a Blood Pressure Monitor, and also on Amazon here.