I think my screen is dead.

If you just reformatted, i would suggest you try to install your graphics drivers. They can be found on the HP Driver website. If the monitor is flickering, or doesnt respond in the way it should... then there should be worry.

Well. I'm using said laptop atm. I suceeded in entering windows.

that's how my screen looks atm. and I formatted this pc like 2 weeks ago. I doubt this issue would arise now. but i'll try. Thanks