Is it possible to use a windows 7 disk image (.vhd)) to boot into Hyper-v on a windows 10 system?
VHD created using Windows Backup doesn't contain boot partition it only contains data. It could be mounted to migrate data to a new VM for example. You will need to use P2V tools such as StarWind V2V/P2V Converter to create a proper VHD/VHDX. https://www.starwindsoftware.com/starwind-v2v-converter