NEVER CHANGE A RUNNING SYSTEM!

This is a principle I should note! But I made a big mistake: I upgraded from windows 7 to 10. What happend: During my work, windows 10 shut down - without notice - and started a update. The result was a destruction of my grub boot system - I use this to select between Linux and Windows. The result was a damage of both systems and I was not able to recover my notebook - so I had to install windows 7 and all my programs again. Thank you Microsoft! I will never use Windows 10 again!