Hello there,

My story is I used to have an activated copy of Windows 10 on my old motherboard (Mobo A), by taking advantage of the free upgrade from Windows 8 / 8.1. Early this year, my motherboard suddenly dead, sent it to vendor for RMA. In the meantime, I swapped with my backup motherboard (Mobo B) and successfully activate it using my old Windows 8 serial key. Just today Mobo A already out of RMA, and I swapped my Mobo B with it.

My problem is Windows no longer recognized this Mobo A, and I've tried reactivating it using the same Windows 8 serial key, but it just won't work. Calling Microsoft was unsuccessful since the lady over the phone told me to buy a new Windows 10 key, since Windows 8 key can only be used one time only to activate Windows 10 (which I had used on Mobo B). Is this true? Do I need to buy a new Windows 10 retail key?

I thought by buying retail key I'm entitled to upgrade my hardware whenever I want, and able to activate the Windows indefinitely by just calling the customer service.