SOAPUI is using 100% CPU

Hi there,
I started a load test and the CPU usage of my system went to 100%. I stopped the test. But my system still runs on 100% CPU which makes everything very slow. It happens everytime when I try to use SOAPUI. I am using SOPAUI Pro 3.5.1. Our company recently purchased 5 licences of SOAPUI.
Thanks.