LCD backlight randomly changes brightness levels

Since a few days ago, my LCD brightness every once in a while will quickly dim (but not turn off) or stay dimmed for a few minutes before returning to normal. It is if the brightness settings were turned down for a moment, then changed back. When this happens, the software to control screen brightness does not work, and even after the random dimming stops, the software will not work again until after I restart.

I've had this happen twice now, both times I was plugged in. The AC power is not being cut off when this happens.

Seeing as how the screen does not shut off (it only dims to what it would be if it were on battery) and that the control software stops working when this happens, it seems to me that this is a software rather than hardware problem.

Can anyone suggest HP control software to reinstall or some setting to check? Or do you think this is something hardware related?

 

It doesn't sound like a hardware issue. Could the power fluctuate enough as to change the backlight's brightness? I doubt it.

You could reinstall the power management software; then the graphics driver (assuming the first option doesn't work). You have nothing to lose by it.