Hey Steve
A few issues with your answer file
* You set the order for the single command to 2, it should start at 1
* When executing a PS script, you either need to set the execution policy to Unrestricted or bypass it when calling the script (-ExecutionPolicy ByPass)
* I don't know whether the script needs input from the user but I would remove it just to be safe
In the end I would change it to;
<FirstLogonCommands>
<SynchronousCommand wcm:action="add">
<CommandLine>C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -ExecutionPolicy ByPass -File a:\bootstrap-win.ps1</CommandLine>
<Description>Bootstrap Windows</Description>
<Order>1</Order>
</SynchronousCommand>
</FirstLogonCommands>
As for why you can't ping it, by default Windows Firewall blocks ICMP so it won't reply to a ping. VMWare tools might put in a Firewall rule to allow it but I'm not sure.
Thanks
Jordan