I'm sorry, but I don't understand what you’re asking. It's going to require a little more guidance, since an oversight results in hours of needless work.
Just in case, I’ve tried the latest Avast build. As suspected, it was not a "magic" solution. The process was: uninstalled the present build, rebooted, used the clear utility, rebooted, then swept the registry for ALWIL/Avast. I still saw a limited user key HKEY_CURRENT_USER\Software\ALWIL Software\Avast\4.0, but could NOT get to the 4.0 level nor could I delete the key. Then I rebooted, installed the latest build (without any skins, simple user interface), rebooted. No problem as admin but the program still hangs as local user.
-- Now how could an Avast key be created that can't be removed? It’s unlikely to have been "corrupted" by anything since Avast was the last thing installed. I even held off installing XP SP3 for that reason. If something could corrupt it without trying, that makes me wonder what malware could do!
I've used the Hang Rep utility and FTP’d a full 650mb memory dump.
-- No one ever answered my question of whether that showed anything?
You suggestion: “mount the HKCU hive of the non-admin while logged on as an admin (either from the Safe Mode, or from a regular Windows mode).
To do this, navigate e.g. to HKEY_USERS, go to menu File ->Load Hive, and navigate to C:\Documents And Settings\<name-of-the-non-admin-account>. Then select the file ntuser.dat. This should make regedit load the HKCU hive of that user to a new key inside HKU.
Having done that, please try to navigate to the Software\ALWIL Software\Avast\4.0 branch”
-- What exactly does that mean? Is that simply “reading” the local hive while running as administrator in safe mode, or is that “writing” changes” to the registry, that might have undesirable consequences?
-- Again, am I only mounting the local user hive while the Admin, just to see if I can navigate to that 4.0 key and see what it's permissions are? Or am I attempting to add your previously suggested additional value to the 4.0 key in the local user hive of the registry?
I don't fiddle around in the registry UNLESS there is a specific key to modify. Once you start talking about hives, it is not clear to me if this is reversable or not. The last suggested registry modification I followed forced me to reinstall, so I'd like to be sure we understand each other.
And nothing that has been suggested thus far indicates to me that my suspicion that this is a permission-related issue is incorrect. If so, your programming team must surely know what the underlying program privileges are to see what could be screwed up and to explain how?
Thanks.