vmware workstation 7 gives message after a few seconds into the boot process :
Kernel Panic and then crashes.
-- so on some W7 machines -- No go.
(This was using a "Bog standard" LEGAL OS-X install disk) - I'm not using some modifed stuff available on the Internet such as the well known "Darwin.iso" for fixing screen resolution etc etc.
Now in answer to your other question the best way of starting a VM automatically is to use vmware SERVER (free download) instead and then the VM's can be started automatically as a system service at boot time.
They can also run in the background which means you (or other users) can access the Virtual Machine directly without having to be logged on to a HOST session.