Ok, after hard restart prompt to begin installation has appeared, how may I decline ? Thanks to All.

There is no message on the screen - just circling mouth mark...

Thanks, but what is realistic time needed for update ? Hours, days... .?

Some how without my permission update of W7 to W10 was started.... It is in process already about two days !!...distroided all my plans...
I have fast internet and laptop ( Acer Aspire S5) so it...