Well first (as long as the device isn't under warranty anymore, as you don't want to void it by opening it up) go in and clean out all dust and debris from the laptop. Make sure the fans are free and clear as well as the vents.
If this doesn't fix it, then your other options are to try and reset the device and see if this resolves it. So depending on what version of Windows you are running, you would need to locate the program on it to do a factory reset. Or you can go and look into replacing the parts that may be damaged/not functioning correctly.
Again, please note, if the laptop is under warranty, contact the manufacturer about having them do a repair or replacement. Don't open it up yourself, as that can void the warranty.