I had to uninstall Avast after this update. I thought it was the Windows updates pushed this week so I did an image restore to mid February and with the Windows updates gone I seemed fine. The first thing I did was update Avast, and it broke me again - no applications or system processes (Task Manager, Settings) would start, they all produced error 0xc0000005. I could only uninstall Avast using Programs and Features if I disabled it, and then I ran AvastClean in safe mode, and now I seem to be running fine. I have no idea what that was about - I was surely protected against viruses if I couldn't run anything! I run Windows 10. I've used Avast a long time but I can't have my PC just being a paperweight so I had to say goodbye to it. I have no idea why this happened.