I have a user who is using Windows XP X64 and his windows installer will not work properly. He is not able to uninstall any application. I have found a kb that asked me to start > Run > msiexec.exe /unregister than msiexec /regserver than reboot. This does not resolve his issue. He is receiving an error that the windows installer could not be accessed. I checked the reg permissions and they all seem to be fine, system has full control over H_K_C_R.