No Display on Laptop

My son's Acer Aspiron 3620 laptop's display has suddenly disappeared. The power light comes on, the dvd drive opens and closes, and I can hear the fans working. I've gone thru the procedure of unplugging the power, removing the battery, and draining the onboard power off, then putting them back - no change.
I've tried it using the power cord only, and using the battery only - same results - no display.
I've hooked it up to a working monitor, done the toggle between displays - still no display.
According to the specs on the manual, it has integrated video.
Anybody got any ideas?
Are we looking at a new Motherboard here?
Thanks.

 

Does the hard drive (HDD) light flicker, and do you hear audible noise from the HDD?

 

The Hard Drive Activity light comes on for about 30- 35 seconds when you first hit the power button, then goes off. Really haven't noticed any noise from the HD.