VMWARE SERVER POWERS OFF

Hello,

Your licence is still valid? a VM don't power off alone..

After that, we need more detail on your infrastructure, do you have juste 1 ESX ? Do you have a Vcenter ?
The way to auto power on a VM after a crash is call HA. Its only available on a cluster ESX with Vcenter.

You have an option in configuration/Startup option to specify the auto power on, but its just when your ESX boots up.

that's not normal for a vm to power off.  can you tell from the windows logs if it's being shutdown for a reason?  

the only reason I can think of for ESX to do it is because of lack fo disk space on the datastore, but that's not normal behavior for that, either.

you can view the recent tasks and events for the vm in the vsphere client, too.  see if there's a reason there.

To repeat what dnam66 wrote, you really need to find out why the VM is shutting down.  

Look at the guest Windows system event log, at the VMWare tasks and events.

if that works then it's your host that is rebooting not the VM.