Have you played with Group policy editor (C:\WINDOWS\system32\gpedit.msc)?
You migh have accidentally set unwanted restrictions. Most of restrictions
are stored following registry branches:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies
HKEY_CURRENT_USER\Software\Policies
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
I'm not sure which policy is restricting your installation. You might find
it with registry monitor (
www.sysinternals.com). Just activate regmon and
then try to install your software. Regmon will log all registry access.
Search references to keys containing "Policies". When you find proper
registry setting, just rename or delete the key. For example there could be
key like:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer\DisableUser
Installs having value 1. You can delete that key, rename it or change the
value to 0
/Nico