Windows 10 Dual Boot with Windows 7 (on different hard drives)

In article
"...winston" wrote:

Nomen Nescio wrote:
In article
mike wrote:

On 11/4/2015 1:47 AM, edevils wrote:
On 04/11/2015 07:06, ...winston wrote:
...
Fyi...upgrading an 7/8x to 10 or clean installing Win10 using an 8.1
key(another upgrade route from a qualifying o/s - 8.1) using the MCT
tool provides a digital entitled license - you will not be issued a
re-usuable Win10 product key - i.e. upgrades to Win10 do not receive a
product key. Your Win10 digital license is tied to the hardware/device
on which Win10 is installed with your license stored online in the MSFT
Store. If you need to install Win10 again (reinstall or clean) on that
same device the digital license will permit that reinstall/clean install
without the need to enter a Win10 key (a Skip product key option is
available) and activate Win10 after athe digital license is validated
for that device.

I am not clear if you need two separate Windows licenses for dual
booting w7/8x and w10, or you can re-use the same w78x "old" license
that was "upgraded" to w10.
Actually, if you dual boot, you are not going to use the same license at
the same time.

I haven't seen the answer to, "does microsoft blacklist your old key
when you upgrade?" I think that's the critical parameter.

I don't believe that happens. Here's why. I have a desktop which I
upgraded from 8.1 Pro. The upgrade went well, however I had many
display irregularities due to an old video card, so I decided to
revert back to 8.1

Well, the 30-day rollback didn't work. It told me that the backup
files were unavailable (they WERE present). After trying a few work-
arounds, none which helped, I reimaged my machine back to its 8.1
Pro state just prior to the Win 10 upgrade. That was over 2 months
ago and my 8.1 system still is registered/genuine.

Just a data point to consider...

That's how it's intended to work. Upgrading replaces the prior
qualifying o/s license (in your case 8.1 Pro was replaced with 10 Pro).
When you reverted back to 8.1 you no longer were using W10's (digital
license and activation) thus un-replaced 8.1 permitting its use after 10
was removed.

The above, for that same device, does not preclude your ability to
return to Win10 at a later point in time - upgrade again during the
'free upgrade Window using Windows Update or MSFT Media Creation Tool
media, or clean install during the free upgrade windows or after the
free upgrade window using the Media Creation Tool media. Optionally,
during the free upgrade window one could clean install 10 and use the
8.1 Product key (retail or OEM).

The presence of the GoBack item is MSFT's method of assuring that you
can revert to the prior o/s and un-replace the prior o/s - it does not
matter if you GoBack within the 30 days or use another means (recovery
media, image, reinstall using media) to rever to the prior o/s.

Winston... One thing I don't get is that I never uninstalled Win
10, I just reimaged over it. As far as MSFT goes, my Win 10 license
was never inactivated, it just has been idle.

What prevents me from upgrading to Win 10 and using my 8.1 image on
another, similar machine? Because that seems to be little different
that what I did.

On 11/4/2015 6:08 PM, Nomen Nescio wrote:
In article
"...winston" wrote:

Nomen Nescio wrote:
In article
mike wrote:

On 11/4/2015 1:47 AM, edevils wrote:
On 04/11/2015 07:06, ...winston wrote:
...
Fyi...upgrading an 7/8x to 10 or clean installing Win10 using an 8.1
key(another upgrade route from a qualifying o/s - 8.1) using the MCT
tool provides a digital entitled license - you will not be issued a
re-usuable Win10 product key - i.e. upgrades to Win10 do not receive a
product key. Your Win10 digital license is tied to the hardware/device
on which Win10 is installed with your license stored online in the MSFT
Store. If you need to install Win10 again (reinstall or clean) on that
same device the digital license will permit that reinstall/clean install
without the need to enter a Win10 key (a Skip product key option is
available) and activate Win10 after athe digital license is validated
for that device.

I am not clear if you need two separate Windows licenses for dual
booting w7/8x and w10, or you can re-use the same w78x "old" license
that was "upgraded" to w10.
Actually, if you dual boot, you are not going to use the same license at
the same time.

I haven't seen the answer to, "does microsoft blacklist your old key
when you upgrade?" I think that's the critical parameter.

I don't believe that happens. Here's why. I have a desktop which I
upgraded from 8.1 Pro. The upgrade went well, however I had many
display irregularities due to an old video card, so I decided to
revert back to 8.1

Well, the 30-day rollback didn't work. It told me that the backup
files were unavailable (they WERE present). After trying a few work-
arounds, none which helped, I reimaged my machine back to its 8.1
Pro state just prior to the Win 10 upgrade. That was over 2 months
ago and my 8.1 system still is registered/genuine.

Just a data point to consider...

That's how it's intended to work. Upgrading replaces the prior
qualifying o/s license (in your case 8.1 Pro was replaced with 10 Pro).
When you reverted back to 8.1 you no longer were using W10's (digital
license and activation) thus un-replaced 8.1 permitting its use after 10
was removed.

The above, for that same device, does not preclude your ability to
return to Win10 at a later point in time - upgrade again during the
'free upgrade Window using Windows Update or MSFT Media Creation Tool
media, or clean install during the free upgrade windows or after the
free upgrade window using the Media Creation Tool media. Optionally,
during the free upgrade window one could clean install 10 and use the
8.1 Product key (retail or OEM).

The presence of the GoBack item is MSFT's method of assuring that you
can revert to the prior o/s and un-replace the prior o/s - it does not
matter if you GoBack within the 30 days or use another means (recovery
media, image, reinstall using media) to rever to the prior o/s.

Winston... One thing I don't get is that I never uninstalled Win
10, I just reimaged over it. As far as MSFT goes, my Win 10 license
was never inactivated, it just has been idle.

What prevents me from upgrading to Win 10 and using my 8.1 image on
another, similar machine? Because that seems to be little different
that what I did.

Here's another data point to consider.
Where did you get the 8.1 license/key??
If it came preinstalled, as I understand it, you got a generic OEM key.
They can't invalidate the Dell generic key???
What am I missing?