A couple of possibilities HPs are notorious for loose display cables. Unfortunately, it is not something the avg person can fix. I have fixed ones even an "experienced" tech couldn't figure out. This fix is about a 15min job for someone in the know. It can also be a bad display - then it probably isn't worth fixing It can also be a bad backlight. If you shine a light onto the screen you will see video. If so it is still classified as a bad display. See above.
Answers & Comments
A couple of possibilities
HPs are notorious for loose display cables. Unfortunately, it is not something the avg person can fix. I have fixed ones even an "experienced" tech couldn't figure out. This fix is about a 15min job for someone in the know.
It can also be a bad display - then it probably isn't worth fixing
It can also be a bad backlight. If you shine a light onto the screen you will see video. If so it is still classified as a bad display. See above.