Security ... think about it!
I’d urge anyone who has already recovered from a BSoD or infinite reboot loop after installing this week’s patches to scan their systems with several different security tools, as the rootkit buried in atapi.sys is likely just there to hide the presence of a larger, more systemic malware infection. Restoring from a known-good backup would be ideal, however most home users sadly do not have backup images to rely upon.
I have found that the root cause is an infection of %System32\drivers\atapi.sys, and that replacing this file with a clean version will get the system booting normally.