Good day
Download windows 10 update assistant or troubleshoot windows update Go tosettings, update & security, troubleshoot, windows update.
Enter the Windows 10 Pro Default key under change product key.
X3W8N-3WQCV-2MXDF-K77MK-7XMP6
Or
VK7JG-NPHTM-C97JM-9MPGT-3V66T
Note: This default key will not activate the system, just take you to Pro so you can activate using a valid Pro key that you will provide.