@Priya4466,
Welcome to the HP Support Community!
I reviewed your post and I understand that you are getting two dark horizontal lines on the display.
Don’t worry, I assure you I will try my best to get this sorted.
I recommend you update the BIOS and the graphics driver from the below link and check if it helps.
https://support.hp.com/in-en/drivers
If you continue facing the issue, then boot to BIOS by tapping the F10 key on startup and check whether you are able to duplicate the issue in the BIOS screen.
Let me know how it goes and you have a great day!
If you wish to show appreciation for my efforts, mark my post as Accept as Solution. Your feedback counts!
Cheers!
The_Fossette
I am an HP Employee