The path you mentioned is there from Avast 5. That means that they have been updating avast since then (about a year).
1_ Backup license file.
2_ Run the removal utility under Windows Safe Mode. Run it several times, selecting for each run each version / edition of Avast you ever had installed (and/or updated, like for example, from avast 5 to avast 6.x). If necessary, correct the selected folder in the removal utility.
3_ Manually search and delete any (hidden) folders that contain "avast" or "alwil" in their names (like, for example, "avast 5").
4_ Under Windows Normal Mode, with the latest stable version of avast, "right click -> run as administrator" on the setup.exe.
5_ After the installation, reboot immediately, without configuring anything else.
6_ Configure, update and insert your backed up license.
The folders of avast are not "static" in size, and they may get to 160MB "sometimes" too, because of the increment definitions updates. After a while, avast "cleans" itself.