HP...since Carly Fiorina took over has gone to crap...but that is another story.
This is a common problem with laptops. There is a current lawsuit against I think Toshiba for this same problem. Bring it back to the place you bought it or contact HP online about the issue. In addition try placing a small book under the back edge of the laptop so that airflows underneath it. Also try not to keep it on wood as it does not conduct energy well and the heat builds up in the laptop.