Activating windows 10 with a used key?

[vkarakostas]

I activated win 10 with on my pc,Then i send the product key to a friend and he activated his copy(Bad idead?),Should i worry that they will deactivate my license??? 

[TetraSky]

Yes, you should worry that they will deactivate your license.

Normally, your friend shouldn't have even been able to activate the license at all, especially if this is an OEM key.

If it's a retail key though, there's a chance Microsoft will deactivate it (seriously you can get a key for less than $40 online... why take the risk of losing your key entirely?) because the terms of service clearly state only 1 computer using the key may be active at any given time.

[vkarakostas]

 

it is an windows education key,i got it for free.