I have a dell monitor that I would like to use as a second monitor to my MBP. I connected the DVI cable from the laptop to the monitor, double-checked the power cables, but the second monitor won't show up in the display preferences. What gives?
Under the display settings hit detect displays. See if that helps. I have mine hooked up to a Dell 2405 and it shows up right away. If you close the lid and use an external keyboard to wake it you can get a better resolution depending on your monitor.