So I bought the DLC back in 2010, but upgraded my OS to Windows 7... now every time I try to install the DLC, I gives me the "You must run as Administrator..."
THERES ONE USER ACCOUNT on my computer, WITH FULL ADMIN RIGHTS...
Is there a workaround this issue? I've already try to "Run as Admin" and choosing Run as Admin from the properties of Origin...
Try this thread. You can try setting Admin rights to Origin, but I don't think it'll work for the Pinnicle Station executable. Are you able to access the executable directly in Windows? If so, you can set Admin rights to the executable and attempt to manually install.
You won't see the exe on your machine. You likely got it through EA, so you need to download their Origin client to handle your digital content. Contact EA support for more info.
In Origin Settings>General do you have 'Keep Game Installers after game installs' checked? My installer is shown as 'MassEffect_PS_ES.exe' so you could try searching for that.