A security torx bit won't cost you a lot, but you could always try the old pencil trick; remove the lead and melt the tip of one of those cheap plastic mechanical pencils, using a cigarette lighter. Push down the melted tip over the screw head, and keep it as still as possible while the plastic solidifies again. With some luck, you can now use it to unscrew the screw 😀

A small slot screw driver usually works too.

It looks like a standard security bit. You should be able to find a security bit set at your local hardware store or online.

If you are careful, you should be able to break off that column in the center of the screw and use a regular flathead screwdriver to remove the screw.

If you don't want to try that, then you should be able to get a security bit set for pretty cheap from a tool store. Here in the USA, I can get a complete set of bits for less than $20 from Harbor Freight Tools.

And if you don't want to spend the money on a security bit set, you can always use a file and cut a notch in the center of the blade of a flathead screwdriver to make it work.. and probably have to file down a slightly wider bladed screwdriver to make it fit just right.

I have in the past cut a slot in the blade of an old small flat blade screwdriver with a hacksaw blade or thin rotating dremel cutting wheel..which allows the centre pip of the securirty screw to nestle in the slot.
This does work ..but you need to be sure to choose the right size of cheapo flat blade screwdriver ..and dont use one with a blade tip made from tempered steel ..
You'll blunt your hacksaw blade before you make the slot.
rgds
VS

Thanks for telling me what it is. I should probably order some tools for this kind of things. Been kind of lucky that none of the previous laptops that I have worked on have had special screws like these. The screws are very tiny, so even my smallest (2mm wide) flathead wouldn't fit there even if there wasn't that middle part blocking it. I just think that it is strange that only location where the laptop has thse kinds screws is the bottom ram door. I have already opened the top cover and replaced the cpu in this laptop.