Risposte:
Secondo http://answers.microsoft.com/en-us/windows/forum/windows8_1-windows_install/hp-proliant-n40l-81-installation-freeze-network/5626c5a5-3240-4ba0-b994-10d10cd7d529?page= 4 il flashing dell'ultimo BIOS dovrebbe risolvere il problema: http://ftp.hp.com/pub/softlib2/software1/pubsw-windows/p1657370250/v93269/SP64420.exe