Help with my internet connection?

So I do have an internet connection - but only when an ethernet cable is plugged into my laptop - can anyone tell me how I can get it so I can get a wireless connection like I used to?

It started being like this when my brother went onto my laptop and did something, and now... well, I've told you. So, is there anything you guys can do to help me? <3

*

In other news, I'm in a pretty good mood at the moment, despite the lack of wireless internet, because I'm going to be writing the news for the school website - apparently the English department in my school said I was really good when it comes to writing, so yay.

But seriously - can anyone tell me how I can get it so I can get a wireless connection?

I'll love you forever if you can help,
Unneeded intricacy