Dead Laptop

Recently one of my users brought in their Dell Inspiron 9100 for me to run updates and routine virus and adware scans. When powering on the laptop something strange happened, I pressed the power button and all that happened was that the power led came on and went back off. There was no signs of it trying to make an attempt to do anything. I have plugged in the power adapter just to make sure and the same thing still happens. I have never messed with laptops as much as I do desktops, some differences between the two, but not many. So any suggestions to what I need to check? So far the only thing I have tried was by putting in another fresh battery in it with the same results.