I have used Avast for at least 5 years without any problems. But while updating from 8.0.1483 to 8.0.1489, when I re-start my computer, it starts up but hangs before the desktop appears, leaving me with a blank screen which I left for an hour.
I have updated twice over the last 2 weeks, but each time had to do a system restore.
I have Windows Vista (sp2) on a 5 year old Dell Inspiron 1501 laptop.