I did this before in the past with a key off of eBay (no indication made by the seller that the key was not legit other than the suspiciously low price) and eve

I did this before in the past with a key off of eBay (no indication made by the seller that the key was not legit other than the suspiciously low price) and everything was fine until it came time to reformat and start fresh roughly a year later - at that point the key no longer worked and the seller vanished from eBay!