please how can i get windows 8.1 with bing to reinstall my toshiba satellite c55-b529?

[MOGK]

i upgraded from windows 8.1 with bing to windows 10 technical preview, and my product key with was embedded in the computer does not activate any more, i wish to reinstall windows 8.1 with bing, activate it before upgrading it please i need help. thanks

 

[terenz]

I hoped you made a recovery USB key that Win 8.1. bugs you to do?