http://kb.vmware.com/kb/1004340 This video details various ways to power off an unresponsive ESX virtual machine. A hung virtual machine may not power off when using the guest OS or when choosing to power off the virtual machine from the vSphere Client. The various command line methods are demonstrated here. For detailed information, and see the associated VMware knowledge base article. This video uses ESX 4.0, but the same basic steps apply to other versions of ESX.
