Hi,
Thanks for your quick reply.
1.My Build number is the same : 19045.5131
2.Yes, I have tried now thru Task Manager, End Task for Explorer.exe and actually did Start button returned to the Center.
3.No, I have very clean Windows, with no other applications running in the background, since it's an audio music producing computer and it's just for this purpose.
Best regards,
Matej