So I've been running a Dell 20 inch external display on my macbook pro since September. I got home today, set my laptop on the desk, plugged it in and plugged my keyboard in, the laptop woke from sleep, and then went back to sleep, then i opened it it woke again, plugged my display in and my laptops screen was black (with the backlight on, and i could see a cursor). I shut my computer down, turned it on. When i moved a window to the second screen I noticed the colour was off, I thought it was a connector but the display was properly plugged in. I then calibrated it (something I've never had to do) and finally noticed that the resolution was lower than normal. I go to change it, and notice that I am now limited to 1440 x 900, which is the mbp screen's native res, whereas the display's native setting is 1680 x 1050. Why is it that I am suddenly unable to choose a higher res? Oh, I tried zapping pram, and that's all I've done so far. Sorry for the long post, hopefully one of you can help. Thanks EDIT: things are getting even more fun now. When I unplug my display, os x still extends my desktop, so I can move my cursor offscreen into a void. I have to hit the mirror displays key on my keyboard to get my windows back into the main display.