Hey there everyone, I have a 2008 15'' MBP unibody.. been using it with a 24'' dell widescreen monitor in dual and clamshell modes for a very long time. Today I tried clamshelling it after doing some apple software updates, and it simply isn't working. Its plugged into the power, my keyboard, ethernet, cordless mouse, and an apple dvi to mini dvi adapter. When I close the lid of my MBP, it goes to sleep. I move my mouse, and it powers up, but instead of my monitor (which is working fine in dual screen mode) becoming the main display, it goes back to sleep after flickering for a second.. and the MBP doesn't enter clamshell mode. I've encountered issues in the past but realized that it was simply something dumb on my part.. such as forgetting the magsafe, etc. All the connections are tight, and the screen works when plugged in... I'm wondering if I could have installed some update that broke something... in any case, I haven't tried clamshell mode in about a month so I can't be sure of this. I'm running 10.6.3, and after trying clamshell, I open my MBP's lid, unplug in the DVI to minidvi adapter, replug it, and while the screen flashes blue as usual.. it never turns on the second display. so weird! I'm not sure if this is a hardware or software issue to tell you the truth, because the aforementioned issue is on and off. Any ideas? Thank you in advance! p.s.. i want to try Portal on my mac badly.. that's how i ran into this issue! EDIT: With a VGA cable and a VGA to minidvi adapter, it works. Guess this means its either the adapter or the DVI cable.