If you want to run GreenLight on VMWare Player then it is very likely that you see a message (during the startup of the VM) like this:
"This virtual machine is configured for 64-bit guest operating systems. However, 64-bit operation is not possible.
This host supports Intel VT-x, but Intel VT-x is disabled.
You need to enable VT-X in the BIOS of the underlying Host
example for a HP Desktop - Bios: