For newbies and lazy people that do not want to read or learn more deeply about multiboot environments, there are other options.
Dealing with Win OSs:
If having 7, 8.x, or 10 bootmanager installed, create and install your VHDs by means of WinNTSetup, it will create for you the BCD entries to Filedisk boot from the VHD on MBR/CSM and/or UEFI environments.
Of course to boot from your just installed OS in the VHD, it will need required drivers to be capable to boot from the Mass Storage device where the VHD is located.
NOTE: Some versions of 7 are not capable to boot natively from VHD, and may also require additionally Firadisk or WinVBlock driver, better use Enterprise or Ultimate versions to avoid this limitation.
Additional boot loader alternatives, (no need to use Ventoy on your internal HD).
On MBR/CSM environments:
grub4dos (MBR version):
Latest version: grub4dos-0.4.6a-2021-10-15.7z 520K
Follow instructions from Wonko on previous post to let you load/run grub4dos (MBR version), and manually edit/create the entries in your menu.lst
Grub2 File Manager of a1ive
And you can additionally download your prefered language version of Grub2 File Manager of a1ive, from here, extract only grubfm.iso on same partition where Win bootmanager and grldr.mbr+grldr reside and add following entry in your menu.lst:
iftitle [if exist (hd0,0)/grubfm.iso] Grub2 File Manager of a1ive - (hd0,0)/grubfm.iso
map --mem (hd0,0)/grubfm.iso (0xff)
title Grub2 File Manager of a1ive - Find /grubfm.iso
find --set-root /grubfm.iso
map --mem /grubfm.iso (0xff)
This will load/run Grub2 File Manager of a1ive from a virtual CD device. Please see first attached picture.
Then on the menu on your screen just navigate to your desired Partition >>> Folder >>> VHD or ISO file (or OS installed on a partition) you want to boot from.
This will avoid the need to create manually the respective entries for each one of the VHDs or ISOs (or OS installed on a partition) in your grub4dos (MBR version) menu.lst
NOTE-2: Grub2 File Manager of a1ive is also capable to boot Linux files. Please see second picture.
ON UEFI environments:
Win Boot manager do not allow to load directly grub4dos (UEFI version) or Grub2 File Manager of a1ive as it does on MBR/CSM environments.
Then it is necessary to boot first from Grub2 from A1ive and from it chainload to Grub2 File Manager of a1ive or grub4dos (UEFI version), but this is a little complicated procedure for non advanced users and it is preferable to use better the programs from wimb to do this automatically for you, please see info on my post No. 2
For additional and more detailed info of all more known recent tools to multiboot on different environments, and/or Win+ Linux multiboot please see this topic: Summary of new tools for UEFI and MBR/CSM boot and Ramboot