Thanks Matthew,
I also tried the uninstall tool and then reinstall, but unfortunately that didn't work. The last time this issue happened I just waited until the next day for the latest Avast update and things were fine. Just to confirm, does Avast do daily updates?
This is a major issue because it almost renders my PC useless for the first 10 minutes or so. I am surprised there hasn't been more cases reported on these forums. If this continues, I will have to go with another anti-virus which is too bad since I have been using Avast for years now.
If it helps, I am running Win 8.1, Samsung EVO 840 SSD, Asus ROG MB, GTX 670.