Hi
Try changing the following line -
2.$GuestInterface= Get-VMGuestNetworkInterface -VM testVM -GuestUser Administrator -GuestPassword pwd2345 | where {$_.Name -eq "Local Area Connection"}
3.Set-VMGuestNetworkInterface -VMGuestNetworkInterface $GuestInterface -GuestUser Administrator -GuestPassword pwd2345-Netmask 255.255.255.0 -Gateway 10.10.10.1 -ip 10.10.10.11
Don't forget your DNS aswell
Regards
Ken