A: Booting Hyper-V VMs via the Preboot Execution Environment (PXE) requires booting that computer from its network card, and specifically a legacy network adapter. Recall that a Hyper-V VM can use either a legacy or a "regular" network adapter. First, a legacy network adapter must be added to the VM; then, the Startup order in the BIOS must be rearranged to start the OS first from that legacy network adapter.

What makes this process confusing is that it's possible to rearrange the Startup order to use the legacy network adapter when no such adapter has been configured for the VM.