Alum. MacBook won't connect to monitor. Please help!!

I posted this thread in the MBP forum a couple of weeks ago but no one had a solution. Since then i've called apple and they couldnt do much. when i connect my macbook to the vga monitor, it works great in mirror mode. but wont work in clamshell mode. when i connect it to other screens, such as my tv, it works great. so the problem lyes in the monitor. why does it work in mirror but not in clamshell? the brand is DCLCD and i got it from newegg. i should also add the monitor works fine when hooked up to a regular computer. what could the issue be? when i wake the macbook up from sleep, the monitor just flickers like its trying to adjust itself. i really hope someone can help!

GfulDedFan said:

The only suggestion that I have is to go over These Instructions carefully and make sure that you're not missing a step.

Are you able to use the monitor in extended mode?

Click to expand...

I'm not missing a step, as i said it works fine with other monitors and tv's. and yes extended mode works, its only when the laptop is closed that it wont work.

unixperience said:

this may be silly, but is the brightness on your computer up all the way before you close it? if my screen brightness is down, I get a flicker when i open it but no picture. maybe give that a go.

also are you using a usb mouse/keyboard or bluetooth?

Click to expand...

Nah the brightness is usually in the middle. and the keyboard is usb and successfully wakes the computer up, just no picture on the external monitor.