Had this issue recently with vSphere. I upgraded a VM to hardware version 7 and rebooted. It showed it rebooted but once it passed the windows splash screen it went to a black screen in the console. I was also unable to ping or RDP to the server. After rebooting it and finding the same thing, I booted into safe mode which worked ok. I wanted to reinstall VMWare tools but sadly Windows Installer does not work in Safe Mode.
I went into Device Manager and found a yellow exclamation on the NIC driver but the display driver showed fine (WDDM driver). I uninstalled and reinstalled both. The NIC driver reloaded as the same driver but showing no warning, the Display driver reloaded with a different driver, the VMWare SVGA II driver. After booting into normal Windows mode, everything was fine.
Quite the headache though