Howto force Windows 7 / Windows 8 upgrade to Windows 10.

1) Stop the “Windows Update” Service.
Run: services.msc
Stop Service: Windows Update

2) Erase the old windows update files.
Go to: C:\Windows\SoftwareDistribution\Download
Erase all the files in this directory.

3) Add a DWORD(32 bit) post to the windows registry.
Run: regedit
Go to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\OSUPGRADE
If you dont have OSUPGRADE create it.
Add a DWORD(32 bit) post with the name: AllowOSUpgrade
Set the Value data: 1

4) Start the Windows Update Service again.
Run: services.msc
Start Service: Windows Update