You can log into an esxi 4.1 host and issue the following command to get a list of all running and registered VMs.

# vm-support -x

The vm-support command above will give you the World ID of the VM that you are looking to kill.

# vm-support -X <World_ID> –w <dir>

Another way to kill or shutdown a VM is with the vim-cmd command. Use the command below to find your vmid

vim-cmd vmsvc/getallvms\

Then kill it with…

vim-cmd vmsvc/power.off <vmid>

The nastiest and uncleanest method is to actually kill the unix PPID (parent process id) of the VM. Take a look at the command below and subsitute your VM’s name. The PPID is in bold.

# ps | grep  <my_vm_name>
10071899      vmm0:<my_vm_name>
10051474 10071896 mks:<my_vm_name>   /bin/vmx
10084243 10071896 vcpu-0:<my_vm_name> /bin/vmx

Reference here