I had the same problem with the pavilion g6 2012, i solved it by unscrewing the one screw that holds on a plate which gives access to the ram, WiFi card and the HDD. all I had to do was pull out the drive, disconnect the sata connector thing and blow out dust that had managed to get under the plastic cover which protects the PCB on the HDD. Then reconnect making sure to push connector in all the way and try booting. I expect the bottom of your laptop to be different but try it and see