I upgraded to Windows 10 from Windows . I cannot open files Pictures, Videos, Documents, Music.why?

[Windows Central Question]

I upgrades to Windows 10 from Windows . I cannot open files Pictures, Videos, Documents, Music..

I upgrades to Windows 10 from Windows . Before that I had gigabytes of important data on files: Pictures, Videos, Documents, Music, Movie Maker files.. but the explorer of Windows 10 says now: Empty file!

This is a terrible disaster!! An a lie by windows because I upgraded because they said " your data will be exactly where it was".

Also my Nokia Lumia 710 Smartphone cannot be opened by Zune. I demand a reset to windows 8. I cannot continue working.,

This together is a grave loss of adequacy in my profession.

Please answer how to reset or what to do...
Thanks
Pavlos