If your running XP, in the power options, you can choose
how ur laptop will react whether it's running on battery power or plugged in...
I'm not sure if you set the "do nothing" when lid is closed will allow it to keep running or not..
all laptops are different... My solution was to remove the screen and sell it on ebay for $100
Others around here have either opened the laptop and disabled lid shut switch or sanded off
the little pin that sticks up on some laptops to trigger this...
Hope that helps!