Do you own a Dell laptop?
If you own a Dell laptop, you might want to look for small cracks in and around the hinges that hold the LCD to the system both on the top of the laptop and the back. I called Dell about a different hardware problem and the guy on the other end asked if I had any cracks. He stated that both the problem I called about and the cracks would be taken care of. I have an Inspiron 8200.
Wally