Wont boot without screen attached

I have this Pavilian, really old, and all the plastic broken everywhere (long story)

I want to turn it into a “MultiConsole” i had dissasembled everything and i think i messed op the lid sensor. so now when i turn it on. the monitor just barely shows hp logo and turn off (Like the lid is closed)

the easyes solution is to entirely remove the screen and connect it to a monitor trough HDMI. i have signal, but it just says “Prepare OS for Boot” (The hdd has a correctly installed system and it boots perfectly)

If i remove the Lid Screen, the system refuses to boot, and it doesnt allow me to enter bios or anything.

Any hints would be really appreciated!