Win7 Ultimate and Win 8 Pro Disks?

I have 2 Retail disks and one PC. Normally run Win7 and Win8 Pro on separate SSD's
Win7 is ran like 99.9% of the time .

From what I read, you can use these CD's on other systems if my motherboard goes bad or I build another system

If I upgrade to Win10 from Win8 Pro and later on from Win7, will both product keys be active ?

Thanks

RE : From what I read, you can use these CD's on other systems if my motherboard goes bad or I build another system

You must uninstall the Win 7 or Win 8 from the computer FIRST, before you can use the disk(s) for another computer.
The rule is : 1 key, 1 install.

RE : If I upgrade to Win10 from Win8 Pro and later on from Win7, will both product keys be active ?

Your Win 7 and Win 8 product keys aretied to the Windows 10 installed. You can NOT use the keys for another computers.

I found this several places. This is from Microsoft

What happens if I change my motherboard?
As it pertains to the OEM licenses this will invalidate the Windows 10 upgrade license because it will no longer have a previous base qualifying license which is required for the free upgrade. You will then have to purchase a full retail Windows 10 license. If the base qualifying license (Windows 7 or Windows 8.1) was a full retail version, then yes, you can transfer it.

I found this several places. This is from Microsoft

What happens if I change my motherboard?
As it pertains to the OEM licenses this will invalidate the Windows 10 upgrade license because it will no longer have a previous base qualifying license which is required for the free upgrade. You will then have to purchase a full retail Windows 10 license. If the base qualifying license (Windows 7 or Windows 8.1) was a full retail version, then yes, you can transfer it.

A motherboard is essentially the computer.
New motherboard = new computer.
While a retail license is transferrable, it has to be uninstalled from one computer first before it can be used to another computer.
Failing that, you will have to buy a new valid product key to install to the new mobo.
That's my understanding.

Why don't you wait a bit for others to fill in the answer.

I had read "stories" about user having a dead mobo, went ahead and bought a new mobo and managed to "sweet-talk" MS into issuing a new product key.
If true, it could only be exception to the case.
I wouldn't count on it.

RE : If I upgrade to Win10 from Win8 Pro and later on from Win7, will both product keys be active ?

Your Win 7 and Win 8 product keys aretied to the Windows 10 installed. You can NOT use the keys for another computers.

Absolutely false information. Nothing happens to the Windows 7 or 8/8.1 product keys after an upgrade to Windows 10. The same rule applies as if you never upgraded - uninstall the Windows 10 on the old computer and use the Windows 7 or 8/8.1 product key on the new computer. 1 product key - 1 Windows install - and it does not matter if the Windows install is the original Windows 7 or the Windows 10 that resulted from the upgrade.

Right from Microsoft:
Recovery options in Windows 10 - Windows Help

If go back isn't available

Check to see if you can restore your PC to factory settings. This will reinstall the version of Windows that came with your PC and remove personal files, apps and drivers you installed, and any changes you made to settings. Go to Settings > Update & security > Recovery > Reset this PC > Get started and look for Restore factory settings.

If you have a product key for your previous version of Windows, use the media creation tool to create installation media for Windows 8.1 or Windows 7, and use it to do a clean install.

Absolutely false information. Nothing happens to the Windows 7 or 8/8.1 product keys after an upgrade to Windows 10. The same rule applies as if you never upgraded - uninstall the Windows 10 on the old computer and use the Windows 7 or 8/8.1 product key on the new computer. 1 product key - 1 Windows install - and it does not matter if the Windows install is the original Windows 7 or the Windows 10 that resulted from the upgrade.

Please read my reply again.

The OP's questions is :
If I upgrade to Win10 from Win8 Pro and later on from Win7, will both product keys be active ?

I said the keys are tied to Windows 10installed and the keys cannot be used on another computer.

The OP did not ask................ what if I uninstall Windows 10.
The OP did not ask................ can I use the Win 7 or Win 8 Pro key to reinstall Win 7 or Win 8 Pro.