Issues with Laptop display drivers on port replicator

Thanatos

So, I had this fucker working exactly how I wanted it to up until recently. The person using it just wants it to display on his external monitor. Unfortunately, it won't let me do that; it looks like a setting for that doesn't even exist in the Lenovo display manager thing. There is a setting to duplicate the display, but whenever I try that, it gives me an error message (the message says something along the lines of "the setting change you tried to make isn't possible: Display Control). It's running through a port replicator, so I'm not sure monitor drivers are going to matter, but I'm going to try installing them, anyhow. Any other ideas?

I've tried fucking with the display control panel repeatedly, too; it absolutely will not let me set the external monitor as the primary display, no matter what I do. There is also a monitor that doesn't exist showing up in there (it looks like a duplicate of the laptop monitor).