Can my dad use my Windows 7?

[Edward78]

I upgraded & have win 10 now is that free or since win10 is using the key is it a no go?

 

[Craig321]

Probably not technically legal, but I bet it'll work fine, especially if it's a retail copy & not OEM.

 

[linktoinsanity]

As far as the licensing goes, the only way you can use Windows 7 really at the moment is on your own machine as a dual-boot.

It will probably install fine, but technically is not properly licensed.