mm.. most of laptops can turn on without the battery (and also if the display is broken, you can still connect an external display if there's hdmi or vga port), but you have to disconnect it: you can disassemble the laptop easily with a normal screwdriver, and usually the battery is connected to the pc board with a white/red wire. just be careful to wear protection gloves and also use an electrician screwdriver (they have extra protection), because the battery and the capacitors might still have some charge. if you are unsure about it, you can ask any pc repair shop, and in case the laptop won't turn on, at least you can take out the hdd/ssd and use an usb hdd 2.5" case to connect it to any other pc and try to backup that data ^-^