Black bird is right, cannot use the older OS that you updated from. No ifs about it. U are allowed to transfer your 8 to a different computer
This is a cutout of my license in pro
There is exceptions to this license, if the license had been declared for reuse by its license holder, do to bad OS not functioning like the call of vista which licenses were reinstated for use.EDIT: Also like to point out with any policy a policy can be broken in the first 2 weeks of the date the policy took effect
EDIT AGAIN:There are talks going on about voiding license with next version upgrade. However your win 8 license will remain for future upgrades