Contact ms, but they may not provide the support for this situation immediately.
They may ask you to purchase a new one, but the price is very high, isn't it?
I met the problem before. considering their service, i gave up.
I just bought a new one from REDACTED after comparing several sites on yahoo, as their price attracted me.
Guess what happens, it worked successfully. hope my experience is helpful to you.
This post is Spam advertising a web site that is almost certainly a scam. Ignore it unless you can afford to throw money away.
As to the OP, no point worrying about your product key - your OEM software will not activate on new hardware. It is tied to the original computer (which you say was stolen).