I don't have extra hardware. Is it possible to install ESXi so that it virtualizes the previous OS that was on the system? If so, can someone point me to the documentation? My google-fu is weak.
What I would do is use VMware vCenter Converter to P2V the virtual machine to an external drive or network share, (by selecting VMware Workstation or other VMware virtual machine as the destination) detach the disk, then install ESXi on the server and import the VM that was created with vCenter Converter.