my dad's laptop, hp pavilion zv5000, screen is not functioning properly. you can see the desktop or whatever is open, but the backlight seems to be not turning on. but when you quickly depress and release a the little rubber knob thing a couple times, the thing that when you close the lid it tells the computer to go into sleep mode or whatever, the screen lights up and you can see the screen fine. so im convinced its not the screen. maybe just the knob? i was wondering if anyone else has had an issue with this labtop or maybe one similar? if anyone has any suggestions taht would greatly be appriciated.