Windows activation an product key???

If Windows 10 was activated before, the most important point is this: a free upgrade from Windows 8/8.1 to Windows 10 uses a digital license instead of a product key in many cases. Also, on PCs that came with Windows preinstalled, the product key can be tied to the device or included with the original packaging/COA label.

Use this path:

1. Open Start > Settings > Update & Security > Activation.
   • Check whether Windows says it has a digital license, needs activation, or shows a specific error code.
2. If Activation shows Change product key, enter a valid 25-character key only if one is available.
   • For a Dell PC that originally came with Windows preinstalled, the key may have been preinstalled on the PC, included with packaging, or attached as a Certificate of Authenticity label.
   • If Windows was bought digitally from a retailer or Microsoft, the key would be in the purchase confirmation email or order history.
3. If the PC was previously activated and there was a major hardware change, run the Activation troubleshooter from the Activation page.
4. If the error is 0x800704CF, Windows did not find a valid license for the device. In that case, use a valid product key from the device packaging, COA label, or purchase confirmation email.
5. If the error is 0xC004C008, 0xC004C770, or 0x803FA071, the product key has already been used on another device or on more devices than allowed. The documented fix is to buy a separate product key for each device. If there was a substantial hardware change and there is a valid key, phone activation may help:
   • In the taskbar search box, type SLUI 04 and follow the on-screen instructions.
   • This does not apply to Windows 10 Pro EDU or Windows 10 Pro for Workstations.
6. If the device date/time is wrong or activation cannot reach the service and the error is 0x80072F8F:
   • Go to Start > Settings > Time & language > Date & time and verify the date and time.
   • Then run network troubleshooter from taskbar search and follow the prompts.
   • Restart the PC afterward.
7. If the PC was repaired or rebuilt and a different Windows edition or different key was used, reinstall the original version of Windows that came with the PC and use the original key if available.

About finding the key on this Dell:

• If Windows came preinstalled, contact the hardware manufacturer for help locating the original key details for the device.
• If the original box is gone, check the PC itself for a COA sticker/label.
• If Windows was purchased digitally, check the confirmation email or Microsoft account Order history.

About the blue screen and automatic restarts:

• That is separate from activation.
• If the stop message mentions something like a page fault, the activation articles do not provide a fix for that crash issue. Activation should be handled first from Settings > Update & Security > Activation, but the blue screen problem is a different Windows troubleshooting issue.

• Find your Windows product key | Microsoft Support
• Why can't I activate Windows? | Microsoft Support
• [Windows 10](https://support.microsoft.com/windows/activation/get-help-with-windows-activation-errors)
• About Genuine Windows | Microsoft Support