/Applications/Utilities/Activity Monitor : This is one way
/Applications/Utilities/Terminal and in Terminal type the command "top" (without the quote marks). Once the readout appears hold down the 'control key' and the letter z. This will stop the readout. With 20 seconds find the PID number and then type the command: kill 111 (whatever the PID number of the service you want to stop /restart you saw in the top menu.