Why isn't my product key working and is blocked by Microsoft?

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Windows Central Question

Product key isn't working and is blocked by Microsoft.

I recently built a PC and it works beautifully, only one problem... my windows 10 isn't activated.
When I originally set up my PC I entered my key and it was verified and it told me restart my computer, so I did, I reentered my key at the start up and it didn't work, so I skipped that step and continued downloading Windows 10.

Once fully installed it still reminded me that I haven't activated windows yet, and despite how many times I try entering the EXACT code that was given on the packaging I always get this error code:



Active member
Jan 12, 2013
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Re: Product key isn't working and is blocked by Microsoft.

We would need more details, especially because this may develop into a sensitive matter. Please create a Windows Central account and respond in this thread.

So, you built your PC - what OS did it come with "the packaging"? If it was a previous version (7, 8 or 8.1), then the key indicated on the packaging won't work for Windows 10 (since the key isn't for Windows 10). Valid/activated Windows 7, 8 or 8.1 OS's are upgraded to an activated version of Windows 10.

You may read more about your specific error code here: Cannot Activate Windows 8 (Error: 0xC004C003) - Microsoft Community


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Aug 26, 2014
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Re: Product key isn't working and is blocked by Microsoft.

That error code usually indicates a blocked MSDN key, where a seller sells you a key for Windows, and continues to sell the same key to as many people as he can before getting caught.

Get in touch with Microsoft, and Microsoft will get in touch with whomever sold you the key. It's the only way Microsoft will handle it.
Protect Yourself from Piracy

If you bought the key on Ebay, you have 45 days from the date of purchase in order to get a refund. Act quickly. You may contact whatever seller you purchased it from and explain the situation to them, and ask for your refund.

The way I see it, the seller made a sale to you for goods that were implied to be fit for a particular purpose. They violated that contract, and also violated a contract with Microsoft if they sold you a MSDN key that they were under contract not to resell. If they would like to remain in business, they would be well advised to refund your money or provide you with a legitimate copy of Windows 10.

This is why when I purchase an Operating System, I won't even purchase it on Amazon. I go to a well-known large chain retail store such as Walmart, Best Buy, Staples, etc. You may not be from the US or from an area that has that easily available, but the best way to obtain it in that case is to purchase it directly from the Microsoft Online Store.

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