Just boot into the bios and check , if it the issue exists in the bios that means it is a Hardware problem and you have to send the NB for the repair ... Haaaaaaaaaaaaaaaaa !!! By the way i'm a technician from HP Notebooks ...
Hi there I had exactly the same poblem with my HP Pavillion DV6700 entertainment notebook. It annoyed me fo some time, I was going to spend 80gbp on a new LCD screen but I got to the point that I had to hold the screen to stop it flickering so basically I took the screen apart (while the laptop was on)and had a fiddle. basically there is a ribbon on the left hand side of the LCD and by putting a few matches underneath the ribbon so that it pulls it tight and presto it will work!
We've found that it isn't the laptop at all. Although sometimes I don't know what HP was thinking when they designed their laptops and drivers. We've found that it is a power issue. For end users using a 2 prong cable they do not have this problem at all. If they have a 3 prong cable then they have the problem.
We are working with an electrician to see what our problems may be. The buildings are old so it might be futile.
Why most of HP Laptops have the same problem? I purchased HP laptop in the middle east coz I thought it is best brand. We purchase an expensive unit knowing it will last for long. Yes it last, it last when the Warranty ends. Whatever HP model it is, all of us are having the same problem. Next time I won't buy HP anymore, I'd rather choose infamous brand. GRRRRRRRRR....
My DV9500 flickers occasionally with the power plugged in however it is almost impossible to use once the power cable is out and it is running on battery alone. If there is an inexpensive solution being developed then fantastic. This may just add weight that it may well be a power problem!
I have no idea why this may be but the below may be of some help
Bought HP G62 second hand with a defective battery so fitted one from previous HP laptop
Discovered the flickering only happened when plugged into mains so unplugged from mains and flickering disappeared - tested repeatedly and definitely the case
But battery charge when disconnected seems to drop rapidly so plugged back in ad no flickering as yet
My suspicion is that a fully charged battery whilst still connected is causing issue - so power management circuitry would appear to be at fault - is battery trying to overcharge?
I've a certain amount of diagnostic experience around suitably 'obscure' issues - I'm convinced the reason why my sound has gone in my 21 year old XJ6 is that Jaguar in their wisdom decided to mute sound unless the audio system detected aerial was extended!