Samsung NC10 BIOS battery?

I bought a used Samsung NC10 netbook. A few LEDs lighted up when the device was first switched on, but the screen remained black. Since there's no operating system on it, I created a bootable USB stick with Linux, but even then the screen remained black.
After some research I found out that the BIOS battery could be empty. But when I screwed it on, I couldn't see it.
Do you know where this could be, or what could be the reason why the laptop does not work?

Oh yes, I have already tried the battery out and in and press the start button for several seconds.

The bios battery can be on or under the mainboard, but there are also notebooks that do not have a battery but a chip. In addition, the notebook can't be replaced in some notebooks, depending on the manufacturer. Whether the notebook is now due to the battery You can't say that it starts, it could also be a motherboard or a display error. Try to find the battery and if possible replace it and if the error is still there you already know that it wasn't the battery It is also not so easy to remove because some cable plugs have to be removed and can be damaged a lot, I would have it done in your place, even if the notebook is used, so you would be on the safe side and do not need to be annoyed if you maybe something broke.