My Hp laptop displayed horizontal lines

To check if problem is with the hardware, restart your laptop and keep pressing f2 key - this will let you to go into the bios. in case you see the lines in the bios - it is hardware problem and you would need to service your hp. it it is out of warranty - try and fix it yourself. disassembke that and refit display connection cable. this will fix the problem. if not - graphics card fault and you need to change mainboard. which is costly. if that will be beyound economical repair - just sell it on e-bay, you can get good price even for faulty stuff.\thanx