Windows 10 unable to start after last Avast IS program update

Chain of events:

  1. Normal Windows 10 start-up. 2) Avast IS pop-up informing new program version and need to restart PC. 3) Windows closes but PC fails to go off. 4) I waited some minutes after all HD activity stopped and pressed shut-down button. 5) Starting PC, BLUE SCREEN, shows Windows recovery procedures, followed by PC diagnostic and message of inability to initialize. 6] Several attempts of step 5 to no avail. 7) Attempt to proceed to Windows and to close and restart as in first and third options of screenshot 1068c, unsuccessful. 8] Attempt of Advanced Options in screenshot 1069c: System Restore, Initialization Repair and Command Prompt, the last one to run avastclear.exe from a pendrive, all followed by start-up attempts, all unsuccessful.

Current situation: Windows 10 remains UNABLE TO INITIALIZE.

Environment: Desktop Intel Motherboard, Intel Duo processor, Windows 10 Pro fully updated. (Details not available for obvious reasons)

Follow instructions: https://www.avast.com/faq.php?article=AVKB33#artTitle

Thanks for your interest. I read the article you suggested and I wonder if it concerns my current condition, that is, there is no Windows operating system running, since it can’t even start. May be you can help me some steps further:
-does the suggeted tool run on DOS after a pen-drive?
-does it aplly to Avast IS as well?
-since according to Windows(?) blue screen diagnostic initialization performs in such incorrect way as to prevent start-up, does Avast Support Tool address this issue?
Thanks again.

Before we dig deeper, can you still boot into safe mode…?

Unfortunately… nope. Through DOS I managed to get to the initialization menu with F8 but safe mode option doesn’t start, it goes to the same blue screen and options described in the initial post.
Thanks.

https://forum.avast.com/index.php?topic=53253.0
Scroll down to “If you cannot Boot the computer” and follow the instructions.