I have tried to upgrade from the .936 to the .938 program. I continued to have the same problems as previously reported (errors starting all programs, ie: task manager, control panel etc).
I have attempted to install the .941 beta. The installation appears to complete, but About Avast still shows .938. Perhaps I am doing something wrong.
I will attempt to uninstall Avast, and install the .941 beta installer tool and report my results
I'm more than happy to help debug this, so if the developers need need additional info (screen shots, etc) please feel free to respond back-channel.