You're still under warranty and qualify for phone and chat tech support. Don't delay. Go to top of this page, click support and choose the appropriate country.

Jack E/NJ 

Have you run the suggested memtest yet?

Jack E/NJ

Have you tried to HDMI out to a TV yet during these BSOD episodes? Use the Fn+F5 or Fn+F6 display toggles while doing so.

Thanks

Jack E/NJ

PS if you mean blue instead of black screen, forget what I asked. If it's a blue screen, have you tried yanking and reinserting the ram modjules despite if it passed the memtest.

I apparently was editing my last message when you responded. Please look at my previous now.

Thanks

Jack E/NJ

Not replace them. Just re-seat them.

Jack E/NJ

iceman>>>So 2 days ago I have decided to restore machine to factory settings. After it I have immediatelly installed all of the updates for Windows 8, uninstalled graphic drivers and updated to Windows 8.1.>>>

I know you won't like this, but what if you again restore machine to factory settings. And then see what happens for the next few days before you try to update anything. If you still get blue screen stuff, then you should request Acer warranty service.

Jack E/NJ 

Right? I'd say with a 51% probably, yes. Why only 51%?  Because the components Acer used in assembling your machine were tested with,  AND ONLY WITH, the Win8 OS and software on its the recovery partition. 

So if it were my machine, I'd try to run in its pristine factory-restored state for at least a day or so if blue screens were happening more than once a day. If less than once a day, I'd try to run it longer before starting to add or update anything. And I'd try not to add and update all at once. As much as possible, I'd try to make sure a blue screen doesn't happen after each new installation.

Jack E/NJ

As far as I know, yes, you can get a Win8.1 full version.  But its activation is not free like the Win8.1 update would be for you.

Jack E/NJ

Your third swing may be a hit! 8^)

As long as it's been running OK under Win8 factory AND you haven't tried to update anything else, you now may want to try to the Win8.1 update, and  only the Win8.1,  again. Don't try to update anything else even if all your hardware isn't working correctly under 8.1. Let it run long enough to make sure you don't get a blue screen. Then, one by one, start installing other updates or software, checking for blue screens after each installation. I know it's a slow process but if you try to update all at once, and you again get the blue screen, you won't know which installation was the culprit.  
  

Jack E/NJ