Nothing Windows can't handle. The problem is, he's trying to install Windows while plugged into a LAN which has infected computers on it. He's getting infected before Windows is fully installed. All he has to do is physically disconnect from the network, format the HDD, reboot, install Windows (using a different network for updating antivirus etc. immediately after Windows setup is highly recommended) and only connect to this infected network after Windows is ready to tackle malware.
If things really come to this point then you should be looking for professional help because hackers capable of creating backdoors in bios chips are not the ones you can take care of by reading books & asking help online.
Good for me I have Windows set up so it doesn't connect to the network on install. Actually skip network setup through my autounattend script. Windows does not connect to the network until I tell it to, after things are well in place.