VM and Windows Activation question....

[ViperGTX88]

Hello fellow LTT members. I recently had to get my MB sent in to asus for a RMA which took long so i got a another motherboard and will be selling the replaced one. Now i did not do a re-install sins the motherboard were similar and did not have any problems reusing my install. I had a free upgrade to 10 done but, i am lazy to do the upgrade again to get a free copy again on this mother board. I am wondering if its possible to do a free upgrade on a VM from 8.1 to 10 using my legit windows 8 key. Would i be able to use the generic key i get in the VM of the free windows 10 on  my Windows 10 to reactivate it like it was a clean install? I hope this makes sense to who ever reads this. I have everything set up the way i want it and all my programs installed, I don't feel like doing the whole upgrade thing again. So is it possible to do it or no? Anyone tried this? If its not possible to do this then maybe ill just reinstall Windows 8 and do the upgrade again when the end of the free upgrade is near. 

[ViperGTX88]

UPDATE: I ended up just reinstalling my legit win 8.1 on a spare 120 SSD and doing phone activation. Then i upgrade to 10 which gave me the generic key and activated on its own. Then I went back to the Win 10 install that needs re activation and changed the key to the generic and BAM.....Activated sins it should work if the motherboard is the same......I don't have to reinstall now and even if i do in the future from tinkering to much and messing up the install, I can go straight to 10 and it should re-activate without a key by giving me a generic key. M$, why don't you let people use there 8/7 keys to activate 10 if the free upgrade is still available? I still had to jump through hoops but, at least i don't need to re-upgrade and install drivers/programs again...