[mothered]

Rather than scanning for hours on end trying to Identify the cause, try this.

Provided the Infection Isn't embedded In the System Volume Information folder and you have restore points available, hit a System Restore obviously back to the date when everything was functioning correctly.

If that fails, navigate to the Advanced Startup Options until you see "Reset This PC" and select the "Keep my files" option. This restores the OS back to It's factory state without losing your personal files. Apps and settings will be lost though.

If the malware has affected your files hence Is still there after resetting the PC, hit a format and be done with It by selecting "Remove everything" (back In the Advanced Startup Options).