I have read the whole configuration, and I think that this constrain could be remove if HKCU (HKEY_CURENT_USER of Windows registry) is used instead of HKLM (HKEY_LOCAL_MACHINE).
The pgAdmin package provided by entreprisedb can be installed without admin rights, but it is an old version of pgAdmin.
Do you think that this modification is possible?
I think it's a little more complex than that, but here's a patch that I think does everything required. The only part I'm not sure about is the VC++ runtime installation, and ensuring that will work for non-admins. Fahar; can you test that on a *completely* clean installation of Windows please? You must run the "install only for me" option before anything else (don't even install VMware tools).