Windows 10: Dual boot Windows 10 & Windows 8.1 from a single hard disk drive

Would like to dual boot Win 8.1 and Win 10

Lenovo Ideacentre Horizon 27 - Machine type: 6266, Model: 57315178, Bios version: EDKT20AUS.

Has Windows 10 Home, Version: 10.0.19042 Build 19042 - with digital license.

Original OS was Win 8/8.1


Current config: Windows 8.1 in one internal drive and Win 10 20H2 on another internal drive.

To go from 8.1 to 10 or vice versa, I need to go bios boot options and change the boot priority.

Like to have both OS' in one hard disk drive.


Already tried the method discussed at:


https://answers.microsoft.com/en-us/windows/forum/windows_10-windows_install/how-to-dual-boot-windows-7-or-windows-8-with/9ac7acc1-2152-4907-a9de-bd507273a57d


Would like to dual boot Win 8.1 and Win 10

----

After I run setup.exe from the Win 8.1 ISO DVD ,

I get the “Windows 8—Preparing…” window

Once completed, I get “Get important update” window.

I click next to get “License terms” window. Once accepted, I get

“Choose what to keep window”

Once I chose an option and click “Next”, it starts installing.

I do not get the “Which type of Installation do you want” where I can chose to install on another partition.

How do I get to “Which type of Installation do you want" option?

Same problem, if I start with a Win 8.1 and want to install Win 10 in dual boot --

I do not get the “Which type of Installation do you want” window.

:)

 

Dual Booting with Windows 8.1


The procedure below will allow you to boot Windows separately or in dual boot configuration.
Here's what I recommend to do:

1. Disconnect the drive containing Windows 8.1
2. Install Windows 10 with one drive connected.
3. After step 2, reconnect the drive containing Windows 8.1
4. Boot up Windows 8.1. Open disk management and take a note of the drive letter of Windows 10 OS.
   NOTE: if you boot up Windows 10, then take a note of Windows 8.1 drive letter
5. Open Admin command prompt and type: bcdboot X:\windows where X: is the drive letter of Windows 10 (Windows 8.1 if you boot from Windows 10 in step 4)
6. Reboot the PC. You should have a dual boot screen.

NOTE: To break off the dual boot setting, Win+R->msconfig->boot and delete the none default entry on the list.

 

Dual Booting 2 x Windows 10 OS Drives (Existing Installs)


It is uneccessary to do all of the above.

1. Boot up Windows 10
2. Open Disk Management and take a note of the drive letter of the other Windows 10
3. Open Admin Command Prompt and type: bcdboot X:\Windows where X is the drive letter noted in step 2
4. Reboot, you should have a dual boot menu.

 

Installing windows off of a USB stick

Step By Step from vista:
From admin cmd prompt

1. diskpart
1a. list disk
2. select disk 1 (replace 1 with your usb drive)
3. clean
4. create partition primary
5. select partition 1 (replace 1 with your usb drive)
6. active
7. format fs=fat32
8. assign
9. exit

Copy Windows Vista's DVD ROM content to the Flash Drive

xcopy d:\*.* /s/e/f e:\ (d being your vista cd and e being your usb stick)

And that's it, boot off your usb disk