Hello!
I am using Home version of Avast on Vista, and have had no trouble, but about aweek ago there was an update. After the new version updated, my computer slowed to a crawl. It would take 2-3 minutes to load most applications (Task Manager and Firefox to name a couple) and almost 5 minutes to shutdown. Ater uninstalling the updates, I reinstalled the latest from the website (4.7.1043) and all was well again.
The only clue I have to it really being Avast slowing the machine down is that the comptuer runs quickly if Avast is not installed. Possibility: Is it getting stuck on VRDB creation? I have my computer stay alive in screen saver while I was gone to work, so I can't be sure. It was still slow after that time and two reboots.
If anyone has an idea, let me know! I have never had trouble with Avast until this past week! Thanks!