Yeah, I've used Avast on XP, Vista, Windows 7 and Windows 8.1 and I've never had any problems. I was baffled as to why Avast would cause this problem on my new ASUS so I temporarily disabled the resident shields and tried to download Chrome and install it and it worked perfectly. To verify that it really was Avast causing the problem, I uninstalled Chrome, reactivated the Avast resident shields and tried to download Chrome again. With the Avast shields active, the small installer program would download fine. When I ran the installer, it tried to start downloading the rest of the browser and it would get about 10% completed, and restart the download. This happened over and over again until I eventually got an error saying that the installation could not be completed and it offered me an alternate source to try to download the browser from. When I deactivated the Avast resident shields and ran the Chrome installer again, it successfully downloaded the browser and installed it without a glitch. I like Avast but had to ditch it for Webroot on my G751JT.
Let me know if that fixes your problem. I would be really interested to know.
Edit: I was typing my reply at the same time you were. Glad to hear that you got it sorted out. By the way, I currently have Avast running on three other systems that are running Windows 8.1. One is an older ASUS desktop, one is a Toshiba laptop, and one is an HP laptop. It hasn't caused this problem on any of the other systems.