Login with SSH to the ESXi host its on.
do the following command:
ps | grep vmx | grep <fullVM name or part of IT>
Then you get a list of all processes.
First number is the process itself
Second number is the parent process.
To kill the entire vm and all processes do:
Kill <processnumber>
Now the vm is powered Down and the task is killed.
Poweron the VM again and you are good to go.