pls help, this is my first mbp but i m quite frustrated i m using LG22inch monitor, it is a vga cable connected to a dvi adapter connected to a dvi miniport. initially i tried to plug it in without AC power, but ext monitor screen is black. I surfed the net for some solutions, it says tat the AC power must be plugged in for the external monitor to work. However, when i plug in AC power, the ext monitor is still sleeping, even though i can detect it in my profile settings.. what can i do to wake it up?? Please help!!