I lost my Microsoft Office Suite on my HP Laptop with Windows 10

If Office came pre-installed on the laptop, a product key is usually not needed to reinstall or reactivate it. Use the Microsoft account that was used when Office was first set up.

1. Close all Office apps.
2. Go to Services & subscriptions.
3. Sign in with the Microsoft account used to set up Office on the laptop.
4. Find the Office product in the list.
5. Select Install, choose the install options, and then select Install again.

If Office keeps returning to the Let’s get started page after activation, reinstalling it from Services & subscriptions is the documented fix.

If the Office copy on the device was one of the preinstalled versions that can be activated without a product key and without a Microsoft account, reinstall it from the Microsoft Store app instead.

If a message says This product key has already been used, that means the key was already redeemed and added to the Microsoft account. In that case, do not enter the key again—install Office from Services & subscriptions and sign in to activate.

References:

• Cannot start Office apps after Office activation
• Reinstall Office from the Microsoft Store app
• "This product key has already been used" error in Office
• How to reinstall Word - Microsoft Q&A