product key

I obtained a product key. somehow during the registration i accidentally got
an additional product key. when i enter the first product key in it says a
change occured to your windows licsence.

pleaese enter the product key aagain

i have tried both keys without sucsess.
after a few minutes both keys come back witha message - authentication
failed with the following error code - 0x800705b4

i have repeated this process several times and get the same results.

any idea what might be wrong
Stephen