I cannot open microsoff

Your Windows 10 product key cannot activate Microsoft Word; activate Windows with that key separately, then activate Word using a Microsoft 365 or Office license.

1. Activate Windows 10 with the card

1. Select Start → Settings → Update & Security → Activation.
2. Select Change product key.
3. Enter the 25-character Windows 10 key from the card.
4. Select Activate.

Microsoft documents Windows and Office codes as separate redemption types and directs Windows activation codes to the Activation section of Settings.^1^

2. Activate Word with an Office license

Word is currently in its unlicensed, reduced-functionality state. This allows documents to open, but editing and other features are disabled until Office is activated.^2^

Choose the situation that applies:

• You previously bought Microsoft 365 or Office:
  Open Word, select File → Account → Sign In, and use the Microsoft account that purchased Office. The Office product or subscription must belong to that account.^3^
• You also have a separate Office product-key card:
  Go to Office.com/setup, sign in with a Microsoft account, and enter the 25-character Office key. After redemption, return to Word and sign in with that same account.^4^
• The Office key says “already used”:
  Do not enter it again. It has already been attached to a Microsoft account; activate Word by signing in with the account originally used to redeem it.^5^
• You own only Windows 10:
  A separate Microsoft 365 subscription or Office purchase is required to use the installed desktop version of Word. The Windows license does not include an Office license.

If you own Office but activation still fails

1. In Word, open File → Account and verify that the signed-in account is the one that owns Office.
2. Open Control Panel → Programs → Programs and Features.
3. Search for Office. If multiple versions appear, uninstall versions you do not use, restart the computer, and reopen Word.
4. If only one copy is installed, check whether the Microsoft 365 subscription is active. Microsoft lists the wrong account, multiple Office installations, and an expired subscription as activation checks.^2^

Do not post either product key publicly.

References

1. Redeem a gift card or code to your Microsoft account | Microsoft Support
2. Unlicensed Product and activation errors in Office | Microsoft Support
3. Using product keys with Microsoft 365 | Microsoft Support
4. Where to enter your Office product key | Microsoft Support
5. "This product key has already been used" error in Office | Microsoft Support