Hello, I have seen these models have this issue out of the box, either when it goes to sleep, or if it is powered down. You will have to replace the control panel, if the machine is still under warranty then you can get with HP and see about them sending you a new one. Also, when you replace the control panel, I would suggest turning off sleep mode, as well as, raising the time on the "inactivity timeout" setting.
Hope this helps......