registry keys: use some special anti-spyware program… it’s hard to keep an list of bad zones for us and delete them…
corrupted installers: maybe the file isn’t fully downloaded (is incomplete) and that’s the reason of unpack to fail… and maybe it is some unsupported version of installer (with different structures, offsets etc) which we can’t unpack… i don’t know, when i haven’t seen the files… anyway - in case of unpack error the files under the installer are not scanned… if you are sure that it is some legal trojan removal tool, you can run it even when avast didn’t unpack it correctly…