Avast won't install

i’ve been downloading Avast for the last 5 hours and it still says “Avast installation is finishing” and is at 99%, I’ve tried deleting Avast so i can reinstall it but i cant open Avast clear and when i try changing the stats.ini file it can’t save.

You need to provide more information for assistance.
What OS? and version
What version of Avast
Any other security software install at the present time