4.7.938 does not fix the problem with Vista x64. At least, not for me. I can't even log into Windows with it installed. I'm running Vista x64 RC1, and have been running avast since I installed Vista several months ago. The 4.7.936 update totally hosed my system after I rebooted as it did everybody else. I did a system restore to fix the problem, and didn't find out it was avast until after I got everything back up and running and avast installed again. When my system finally crashed a few minutes ago, and I had to reboot, I did an update to 4.7.938 from safe mode and the problem still exists. I get to the login screen, click on my name, and enter my password, then Windows says "Logging OFF" and my monitor goes into sleep mode as if it's not getting a video signal. I then have to hard-reboot my computer and log in in safe mode (where I'm writing this from). I tried uninstalling 4.7.938, then reinstalling 4.7.936 from the website and updating to 4.7.938 before I reboot the computer. The same thing still happens. I can log-in to Windows normally as long as avast is not installed, but if either 4.7.936 or 4.7.938 is installed, I cannot log in at all except through safe mode.