আপনি have no hope to ever see the computer screen again! The power of the older brother is limitless! He has the ultimate authority over আপনি and আপনি cannot do anything about it!
অথবা আপনি could tell your parents he's watching porn অথবা something. That might work.
Do আপনি have a fake insect in your room? Like, one of those fake cockroaches and spiders? If আপনি do, then grab one and secretly place it on him. He could get up and panic. Then আপনি can try kicking him out of the room. xD
Try to lure him out দ্বারা using something he would be interested in. If this doesn't work, আপনি can always mention that to your Parents. If nothing gets done in this case either, welp, tough luck as the authority of an Older Brother is absolute just like it got mentioned before me !!!!
You're gonna have to lure him away. Luckily we know exactly what he likes. Computers. So we're just going to have to leave a রুটি crumb trail of computers leading to a giant rabbit trap with a computer inside of it and then as he's following it, আপনি will have your computer back.