Solved dual operating systems on 2 hard drives

[GUPPY6970]

I have a HP desktop with Windows 7 Home installed.
I would like to install Windows 10 Pro on a second external hard drive.
I can not get to the main Hard Drive to disconnect it.
How can I install the second OS with the first OS installed?

 

[samuria]

Windows wont install on an external hard drive

 

[townsbg]

How to install Windows on an external drive | PCWorld

 

[RolandJS]

Awhile back, booting either the DVD or USB MR7 boot, I cloned my internal HDD containing my Windows 7 Professional onto an external USB 1TB HDD; that sucker actually booted up while being attached to one of my two laptops. I quickly restarted and removed that clone and shelved it -- it is only meant as a backup.

 

[townsbg]

I would only attempt on USB 3.0 or 3.1 because with 2.0 the bandwidth would be so low that it might be impossible to do anything. You might have better luck running a very lightweight version of linux than Windows.

 

[RoWin7]

The hardware lover in me is curious why you can't get at the HD. Can you get the cover off the machine? If not, give me the model # and I'll find the manual.