Avast killed my laptop!

[REDACTED]

Hi all,
this is my story:
I am a software developer and I do my daily job on a Lenovo Thinkpad.
At some point, I had the "brilliant" idea to install some antivirus software to replace the builtin Windows defender service.
Sadly, I chose to install Avast...

I soon discovered that the Avast service was using lots of CPU time, even after I temporarily disabled the antivirus.

I know this kind of thing may happen, with one antivirus working worse or better than Others depending on the specific system configuration.
So, no worries... again, I had the "brillian" idea do uninstall Avast trying to move to a different av software.

Uninstallation complete. You have to restart.
I did restart, indeed... and BOOM, BSOD. 
My workstation is gone. 
It claims that the ACPI.sys file is missing or corrupt.

I've unmounted the ssd drive and i've inspected it on another pc... the Acpi.sys file is actually missing, as well as other hundreds of files in the Windows\system32 folder.

I've tried to recover them from a working pc, but finally i've decided to backup my files and do a full system re-install.

So... thank you Avast! I'm never coming back again.

[Staticguy]

Sorry for your troubles gianni.t. Well to start things off you should only rely on only 1 antivirus program. If you are happy with it. Stick to it. You will only know how many times you switched from one different antivirus to another or you may forget previous antivirus names that was installed. You should have also used previous antivirus uninstall utility, because sometimes add/remove solution doesn't remove all remnants of previous uninstalled antivirus. It leaves some files and registry behind it and that's where the uninstall utility comes in it will remove them and make sure the new antivirus will work well.

Before you uninstall avast. Please run this tool called Farbar http://www.bleepingcomputer.com/download/farbar-recovery-scan-tool/

Make sure you click on the correct download 32-bit or 64-bit. If your computer is 64-bit then download and run the 64-bit of this tool. After it runs it will give you two logs. Make sure you attach these two logs in your next reply. I will notify an experienced user to have a look at your issue and from there he will instruct you further of what to do about the two logs.

At some point he will tell you to uninstall avast via add/remove and follow the instructions. Run the avast uninstall utility https://www.avast.com/en-nz/uninstall-utility. This tool will let you know that it will run your computer in safe mode automatically and follow the instructions.

Don't uninstall avast just yet. Attach those two logs and wait for an experienced guy to help you look at it. I will PM him right now to help you out.

[REDACTED]

Hi, thank you for your reply.

I would be very happy to help you investigating this issue, however, it's really hard to run any of the suggested tools on a system that does not even boot!

I have no choice here than recovering my Whole system to factory defaults and re-install all my development environments (again!). 

And, FYI: this was the FIRST (and maybe last...)  antivirus software I ever installed on this laptop.
Again: this is my main workstation, I usually don't go messing around with continuous software installation/uninstallation.