Hi,
for one of the user accounts (my own) on our home PC the avast GUI freezes after being opened, ie the avast window shows but is non-responsive. Drastic reinstallation of avast seemed to help as long as I remained in the free, limited version, but as soon as I activated Avast internet security, the GUI started freezing again. For other users (wife, children, admin) on the same PC there is no problem.
Cause:
Avast GUI freezes immediatelly after opening when Holdkey (http://www.holdkey.eu/) is active
Solution:
Quit Holdkey is the only solution I found
Have you tried reversing the installation order of Avast and HoldKey ???
I use the portable version of holdkey