I'm trying to connect my MacBook Pro (model 7,1 late 2010) to a desktop monitor (Samsung 906bw) using Apple's mini-display-to-dvi cable. When I connect: (1) my dock disappears from my laptop and appears on the monitor. (2) The desktop on the monitor is not the one on my laptop, but the generic scene (purple rays against the cosmos). (3) I opened a video, which appeared on the laptop but not the monitor. (4) Then my cursor has disappeared on the laptop and appeared on the monitor! (I had to disconnect the cable to get the cursor back). What am I missing? Can anyone suggest a cure for this? Many thanks.