then 5-10 seconds later the pic will reset.
Is it a Pic or an Arduino? This is an Arduino forum.
You are ether taking too much current from the supply, a meter will not give a good reading of such a pulsing current.
Or you need some decoupling capacitors across the supply.
Do you know if the current is limited to your buzzer? How are you driving it?
It should be silent after the sound it done but the power remains at peak until the atmega resets.
Why? It will depend on if the silent state of the output pin is high or low.
Try doing a digital write low after the tone has finished.