Windows 10: How can I remove the current Windows Pro version and reinstall the previous version?

Hello! I recently had a system crash and a 'friend' helped me reinstall windows on my computer. They found a windows product key online for Windows Pro because we couldn't find my original product key. Long story short that worked until now and I am getting the error message "We can't activate Windows on this device as we cant connect to your organizations activation server. Make sure you're connected to your organizations network and try again. If you continue having problems with activation, contact your organizations support person. Error code 0x8007232B."


When I purchased my computer the windows 8 was already pre installed.


I have since found my original product key by following the steps on your support site and wish to remove this version and reinstall windows 10 Home if possible. if so, how? I have tried going through recovery and refresh steps and it just takes me back to the same version.


When I go to change product key I get error message "The product key you entered didn't work. Check the product key and try again, or enter a different one. (0x004f210)"


No changes have been made to my hard drive when the system crashed. Any help you can provide would be very helpful! -Thank you!

:)

 

3DMARK05 no install (remove previous version)

Just like the title says .I couldnt remove old install with add remove so I removed all folders and registry entries for 3DMARK05 but still same error remove previous version then the app stops the install . Big Time Bummer*Bang Head :banghead:

 

erase previous version of windows to create space

Perform the steps to delete previous version of windows :-

• 
  In the search box on the taskbar, type settings, then choose it from the list of results.
  
• 
  Select System > Storage > This PC and then scroll down the list and choose Temporary file
  
• Under Remove temporary files, select the Previous version of Windows check box and then choose Remove files.

 

Downgrade and reinstall the previous version Windows


Do you know if it is possible to downgrade from v 1809 and reinstall the previous version (V1803) starting from the iso file, keeping my applications and documents, having cleaned the disk and removed the previous version?

Thank you