Dell inspirion 1721

My son has a Dell Inspirion 1721 laptop. He did buy it used, but has had it for almost a year with no problems. He took it to his girlfriends yesterday and she was creating a playlist of music when it just quit working. He had it plugged into AC power (and had battery in). He said the screen just went black.
I have searched on these forums and have tried several of the suggestions (taking battery out/unplugging AC, holding power button 45 sec, etc). When you hit AND HOLD the power button, the batter icon/light will come on a yellow/orange color and the blue power button will flash blue every couple of seconds but I do not hear the fan come on at all. If you just hit the power button the batter icon/light will flash on yellow/orange once but won't come back on.
I am afraid something serious has fried for some reason (hd etc) .....does anyone have any other suggestions to try? I even tried taking the panel above keyboard off to make sure the plug in to screen was seated correctly - had an old one where it had come loose and it acted like was no power going to it) And everything looked connected tightly.
Thanks ahead of time for any suggestions.