So I need to make presentation to school about anything computer related... Seriously, anything! Any ideas?

Functional programming is an interesting paradigm. Why not?

Blockchain. It always sounds interesting and novel

Cryptography, more people need to know about this. An be practical, show them how to encrypt emails with gnupg and so on

Why windows has a refresh option.

Brainfuck?

I used to do a topic on Computer Security, and dumped my school's FoxPro database live in class. The VFP client contains the DB password, so all I need to do is decompile it. Also found some school backups later which give me every school system's credentials and every databases out there.

The teacher was cool with it because she thought it's a feature of the school system. Kinda funny to see my friend's reaction though.

How about interdependency of mathematics and computers.I can send you the presentation if you need

Evolutionary algorithms

Why the Internet was down for a day-- the Mirai botnet.