20" Cinema Display to Macbook Pro??

I recently found an older 20" Cinema Display at a yard sale. It was super cheap, and they said it worked great, so I took their word for it.

It has a bundled cable deal that seems permanently attached to the back of the monitor, has some sort of power brick midline, and then has a DVI, USB and Firewire connection. I bought a Mini DisplayPort to DVI adapter off Amazon.

Problem is, all I'm getting is a black screen on the monitor. The LED on the monitor comes on, but nothing on the screen. The laptop does seem to be finding the monitor, and it even seems like it's "there" in that I can drag windows completely off my laptop screen...but still, nothing but black on the display.

So, is it a bum monitor? Or am I doing something wrong? Any way to make this work?

(My laptop is about 2.5 years old...13" Intel i5)